Fencer has been asking for a couple of questions about the rules of international checkers.... which most likely means he is working on programming it. (not a guarentee - but why else would he be asking about the rules)
My suggestion - list the top 2 or 3 checker variants that you think would attract the most players - and post detailed rules about each of them here. Hopefully if Fencer is still in a programming mood, he will take up adding a few more checker variants. (and as he is programming 1 checker variant - it is usually easier to program other checker variants)