In looking through forums for sale, including history, I think finding an entire transfer section+gears/etc is about impossible.
What isn't impossible though is buying a full 6MT, swapping the transfer section, and re-selling it as a non-DCCD 6MT. An awful lot of people don't bother even hooking up a DCCD controller after they do the swap. Finding one of those people and doing a trade seems plausible.
Might be a long term project for me. I'm also looking for a full DCCD transmission for my RS, so maybe I'll poke at the plausibility more once I get into that.