BIG BAD WOLF: Legan is an example of having both a special setup, and special rules: the pawns move diagonal and hit straigth (somewhat like Berolina, except that there's no choice in direction). And the pawns don't promote anywhere.

But I like the basic idea of your suggestion.

You could go even further:
- pick a board size (no reason to limit it to the 6x6 .. 10x10 we have now)
- pick a set of pieces to play with (standard pieces, janus, amazon, archbischop, marshall, grasshopper, nightrider, etc (lots of pieces to pick from at chessvariants)
- pick a setup (standard, legan, fortress, legan, screen, crazy screen)
- pick zero or more additional rules (loop, recycle, cylinder, berolina, dice, ice-age, dark, atomic, anti, 3-checks, etc)


So, wanna play anti-atomic-ice-age-dark-cylinder-dice chess on a 13x7 board, using 10 janusses each?