D'oh. :P
Well, if you like TVPaint it should work on MorphOS. I've heard that some people also got PPaint to work. Though I haven't given it a shot. :P
My Pegasos has FXPaint (MOS), ImageFX (with PPC modules), Art Effect (68k) and DrawStudio 2 (68k) installed. (DrawStudio needs to run the smartwin hack in order to run unfortunatly. This hack may not work in future revisions of MOS.) I also use Cinema 4D (68k).
Don't worry if an application is Amiga 68K, MorphOS's JIT makes the applications run a lot faster then you'd thought possible. ;)
Steph