This ship is listed in LUG's defunct 'ships of the fleet: TOS' manual as an early era upgrade to the USS Daedalus. The description actually loosely matches a ship shown in Starfleet Museum, though the registries and class names are completely diferent.
For this, I basically added the 'rounded hull' and tweked the warp engines and secondary hull as a slight progression to the Baton Rouge. The lines are getting messy, though - more proof I need a good vector-based drawing program. Alas.