I'd personally like to see a freely available, softloadable, update to SpriteExtend that will cope with alpha-transparency. If it could also support the standrard RGBA format then that would be brilliant too. ROL shot themselves in the foot here by not releasing their update to the wider masses and make it usable for developers (even if !Paint etc couldn't edit them, applications could use them.)
The current solution here (Tinct) is really not acceptable (as you know, it was originally written purely for NetSurf and has to contain horrible hacks for printing.) Also, by not being centralised it stops hardware accelleration, and doesn't support anything other than scaling -- CSS3 image-orientation anybody?