Yes this question crops up now and again, and the consensus has always been it would not be viable, even if DCE released the schematics.
The only solution is a completely new PPC card built from the ground up, but when asked at Amiwest last year Jens Schönfeld dismissed the idea, so is unlikely to come from Individual computers. The only other small ray of hope I see, is if you listen to the speech Trevor Dickinson made at Amiwest this year, from 32 minutes into he mentions that three new hardware contracts have been signed with Varisys, so some wild speculation on my part, but at least one of these could *potentially* be a new PPC accelerator card aimed at classic Amiga's.
http://www.youtube.com/watch?v=7PdywsoOPmI
