Today I found hidden ships and SP Non-Playable vessels and I thought "How about seeing if I can make some playable.." I am now making a mod called Forgotten Ships. An one man team is making the mod (me) and it will only for TB2 (since I am using the mod in Legacy) and hope to get it released this month.
EDIT: TB2 unplayable ships will be edited and be playable in this mod.
Generally the 3 things that have to be changed are ..
Startyear EndYear Commandpoints
Commandpoints must be 1 or higher. Start Year and End year have to placed so the ship is flyable in one of the eras ENT, TOS, TNG. And the ship must be assigned to a "Flyable" Race.