So we all know that the Song and Shadow sourcebook was never released, which is a great pity, I am sure you will agree. Unfortunately I have not be able to find in the same stroke of luck that gave me Fields of battle, but I did find something.
I don't consider it possible to recreate what decipher envisioned, but we can try to salvage what is left and restore what we can.
Right here on this forum, I found a post, that gave a glimmer of what they had in the working, and it is this piece of information I have analysed and want to extend with your help:

The most exciting parts of the book, for me, are the rules for Great Tales and Songs of Power, which both give minstrels a lot more to do at the game table. Although you won't be able to use it without the attendant rules, here's an preview Song of Power from the book:

Song of Elbereth

A! Elbereth Gilthoniel!
silivren penna míriel
o menel aglar elenath,
Gilthoniel, A! Elbereth!

-- The Return of the King

Song Picks: 3

Perform TN: 25

Effect: The Song of Elbereth works strongly against the power of the Shadow. First, it acts as a counterspell (see page 170 of the core rulebook) against any sorcery cast or active where the song can be heard. The singer’s Bearing is used to oppose that of the caster. The song can break enchantments as well as prevent them from being cast. Second, it causes pain to all servants of the Shadow (in game terms, those who are Corrupt), imposing a –1 penalty to all tests. Finally, it inspires all enemies of the Shadow. Any who are adversely affected by fear may make a new Willpower test every round that the song is performed. If the result of this test indicates a lesser penalty from fear, they move to that penalty. If it would worsen their situation, it is ignored.

Description: This is a hauntingly beautiful melody, poignant but filled with hope. The normal words are those given above; longer versions are recorded elsewhere in The Lord of the Rings. It is unusual among songs of power in that almost all elves know the tune and the words, and it is very popular among them. However, only true minstrels can get the full effect of its power.

This ability was clearly meant for the Minstrel, or an minstrel like Elite Order, and has three vital components which we can put in the works:
Song picks: This is obviously a function identically to the spell picks, and would be unlocked by a relevant ability which gave the character 3-5 Song picks, and allow the character to at least pick between a selection of power songs or verses, but perhaps other things as well.

The Perform TN is fairly high, and that seems to be fitting, considering the effect which is quite powerful, and the general idea of pulling something like that of with a 'mere' song. The question is how low would a TN for another song go, and how much time do the test require. my guess would be down to 15 and a f/r based on the effect, which seems to have an instantaneous effect in mind to counter imminent evil.

The effect is based on an established feature in the system and expanding on it. The effect is quite substantial and powerful, but it is also quite utility and support minded. It is also implied that a character can continue to perform it beyond one round, until failure or distraction. Other effects we can assume would work in the same manner, but also in less powerful ways.

So the question is, can we recreate more songs and verses to fit this ability and give the Minstrel, or an Tom bombadil inspired elite order, a great new weapon in his arsenal? I have already found some ideas based on actual songs from the books and films, and some without a song as inspiration.
I also suspect that someone among the Hall of fire staff had the original book in their hands, since the Songcraft and Talecraft ability have a familiar feeling (I will upload it for your reference). Why didn't they pass it on? legal reasons properly, since it is a play test work. I as a dane have feared a lawsuit in my life and as such have no such scruples ^_^

So I would like your creative help to revitalize this lost gem, and nothing is a bad idea here I can assure you.

My ideas so far in an unfinished form:

Title
Tom sings a sort of exorcism to banish the Barrow-wight:

Get out, you old wight! Vanish in the sunlight!
Shrivel like the cold mist, like the winds go wailing,
Out into the barren lands far beyond the mountains!
Come never here again! Leave your barrow empty!
Lost and forgotten be, darker than the darkness,
Where gates stand for ever shut, till the world is mended.


Song picks: 2 or 3
Perform TN: 20 or 25
Effect: fear effect on wights and ghosts. Superior, banished for 2d6 hours. On extraordinary success, the wight flees or is destroyed
Description:

Truly rousing words
Song picks:
Perform TN:
Effect: Extend the effects or duration of inspire
Description:

Empowering ???
Song picks:
Perform TN:
Effect: grants increased effect to a spell
Description:

Song of Durin
Song picks:
Perform TN:
Effect: instills hope for the future, assists in craftmansship
Description:

Elven lullaby
Song picks:
Perform TN:
Effect: brings joy, dispel grief and brings about pleasant surroundings in regard to healing. increase weariness recovery
Description:

The Road goes ever on and on
Song picks:
Perform TN:
Effect: Travelling speed increased, bonus on weariness tests related to travel.
Description:

Song in the woods
Song picks:
Perform TN:
Effect: dispel shadows? Grants a sign of the path before you
Description:

Warning of winter
Song picks:
Perform TN:
Effect: ???
Description:

A Rhyme of Lore
Song picks:
Perform TN:
Effect: provides a lore bonus, regarding the men of the west
Description:

The long list of the ents
Song picks:
Perform TN:
Effect: A bonus for lore/race and Lore/wilderness
Description:

In order to revive Merry, Pippin, and Sam after getting them out of the barrow, Tom chants:
Wake now my merry lads! Wake and hear me calling!
Warm now be heart and limb! The cold stone is fallen;
Dark door is standing wide; dead hand is broken.
Night under Night is flown, and the Gate is open!



Song of Oloré Mallé:
This song allows a character to cling to life a little longer. For up to 5 minutes? Or until the performer ends, may the character keep a single target alive, even though he have no more wound points.

Jarring Song:
Make an opposed Bearing check against a spellcaster, if successful the jarring song forces the spellcaster to reroll his willpower check for forming the spell (see path of the wise alternate spellcasting rule) with a -2/-3 penalty.

Song of Biting steel:
For 1 min all sharpened metal weapons of the performers choosing adds +1 damage

Song of fury
Reduce injury penalty by 1? More effects? +1willpower vs fear, +1 armed combat

Moonlight Shadow
This may only be cast on a moonlit night or in daytime in an area with considerable shadow. The performer calls to the shadows, causing them to deepen & thicken imperceptibly over a period of 1d6+ Brg mod rounds. Adds a -1 penalty to light and darkness penalties. Adds a bonus for stealth checks

Song of Valour
Defence bonus of some kind

Counterspell song, for each of the spell categories (air, beast, fire, mind, water and maybe even secret fire?)

Riversong
???

Song of battle
Adds bonuses for the first round of battles

Song of mocking
???

Song of wisdom
???