I wouldn't suggest limiting them by their label, but by the offensive position you set them at. You can play a center at pg and reassign to SG or SF, but not PF, C.
SF's would have a little more flexibility. As you noted some SF's can play all over the court (Odom from SF-C, Lebron from PG to PF, etc).
I think there's a myriad of ways you could create a training system to make cross-training feasible to replace the square-peg-round-hole solution we have now. I'm sure there are some low-cost to programming and maintenance options as well.
"Well, no ones gonna top that." - http://tinyurl.com/noigttt