Thanks to an anonymous poster for this link. There is a NZ focused MythTV site called "Gossamer Threads" that has a developement forum for MythTV. There is at least one small thread discussing compilation issues on PS3 ... its http://www.gossamer-threads.com/lists/mythtv/dev/242005 .
Unfortunately my PS3 doesn't exist yet or I'd try compiling it myself. There isn't a store selling even the basic model for under $1000 ... so I'll wait for the reasonable prices to come .. But please post a comment on any success /failures in compiling on PPC especially if its on a PS3 so we can try to community fix the problem.