I see that there is a sudoku game with Pappocom puzzles available for the PSP (Go! Sudoku). I would argue that the Nintendo DS's touch screen makes it more suited to a sudoku game than the PSP. Anyone who has played the sudoku puzzles in the new DS game Brain Training will be aware of how well the puzzles work on the DS.
So how about producing a game with Pappocom puzzles for the DS?