[Haskell-cafe] Source of 16x16 Sudokus?

Folks: For research on the behavior of parallel Haskell, does anyone know of a source for graded (easy through evil) 16x16 Sudoku puzzles? Our hardware runs too fast for us to get meaningful timings on 9x9's. I suppose we could insert time wasters, but I think that would also distort the results . . . . Thanks in advance, Murray Gross Brooklyn College