Non-Canon paper in Selphy CP730
I think it would be a big risk.
I've always stuck to the original paper/dye packs with my Selphy. If it were that easy I'm sure some of the independent manufacturers would have cashed in on the market.
I know what you mean about the postcard printed back though. There are times when I wish some of my prints were plain on the reverse.
Photographers feel guilty that all they do for a living is press a button. - Andy Warhol