Supposedly this guy was making them for the Mopar Turbo guys that were using 904s

Donato Engineering
2934 E. Maple
Milfiord MI 48381
Tel: 248-676-8554
Fax: 248-676-8286
Contact: John
donatoeng@aol.com

These guys have them listed for 727s and other varients, Give them a call they might have them?

http://www.transmissioncenter.net/hardened_shafts_and_drums.htm