No idea if this is possible but here goes....
Could a character who has TRed use the Altars on his ship to craft add enhancements to an item which is crafted by another character?
I know that the GS blank is BtC, but I'm not sure if an item that another character made from his own GS blank is. If that's the case, then it could be crafted by the other character into whatever item the TR needed (I see un-enhanced GS weapons on the AH occasionally, but I don't know if they are random loot- never seen one drop- or if someone just has that many extra blanks) and then transferred to the TR before enhancements are placed upon it and it becomes BtC.
I can't believe that this can be done....but you never know.