Jim,
The only semi-production that I know of is Lee Holman
lee@holmanmoody.com. The last time I talked to him about the transaxles, he was going to build them 3 at a time and had 3 magnesium cases fresh from the foundry. He was looking for someone to machine the cases at the time. That was ~3 years ago. I have no clue what has transpired since then, but as I recall, they had a price tag of ~$30K or at least that was the price he gave me.
Shop Address: Holman Automotive Inc., 9119 Forsyth Park Drive, Charlotte, NC 28273 (He is no longer at the airport)
Mailing Address: Holman Automotive Inc., PO Box 669351, Charlotte, NC 28266
Phone (704)583-2888; Fax number (704)583-2890