I Make all my own decals, mostly on an Alps-1000 printer with waterside decal papers, 8.5" x 11, 8.5 x 14 or 8.5" x 17" I create my decals in Corel-10 or Photoshop-6.
I've also been experimenting with waterslide "inkjet" papers. They seem to be ok, now having improved greatly in the last year. But the colors are still off.
This looks like an interesting site, will have to explore in time.