The first Knightmare Chess set is out of print, but set 2 is still available. http://j.mp/3VsN6I
I have both sets. The kids use it to keep me from winning and to generally frustrate me. The art on the cards is fantastic and the rule mods really make you change your tactics…or throw them out the window altogether. Definitely recommended unless you’re a chess purist.
We also have Tile Chess (same publisher). Makes for a chaotic multiplayer chess variant. No board required, every piece much touch another, no pieces can be orphaned. http://j.mp/cjtAfU
GOG.com has Battle Chess Special Edition for $5.99. It includes the original Battle Chess, Battle Chess II: Chinese Chess, and Battle Chess 4000.
http://www.gog.com/en/gamecard/battlechessspecial_edition
I bought Battle Chess when it was released on the C64.
OK, that’s a little depressing.