I'm a big fan of rules that can be distilled onto a single sheet. I don't think that will be possible with A Band of Joyous Heroes simply because of all the spell and creature descriptions that take up too much space, however, I can still make the attempt!
Yesterday I sent my latest draft of the first card: Actions on the front and Combat on the back. See above for what they look like. The are derived from the Dark Passage naval game I ran a year or so back. I'll be providing a detailed explanation later. Right now I'm trying to get ready for Cold Wars.