Do you know the 'Game Courier' on-line playing system of chessvariants.org? It seems this is designed for easily doing the thing that you want. It would require you to make some 'preset', basically a game definition, and that is it.
Some time ago I also designed a kind of server for turn-based Chess games, and configured it for Chu Shogi and Serawan Chess ( http://hgm.nubati.net/schess/play.html , although it doesn't seem to run since they upgraded the server to 64-bit). To make it usable for any Chess variant with just changing the graphics on the html page, I did not have it check any rules, though. It was just intended as an on-line replacement for a wooden Chess board.
But it would not be very difficult to expand the JavaScript client to impose rules for a specific Chess variants. I already made a page that highlights possible moves of various variant pieces, for the purpose of explaining the rules of Chess variants. E.g. http://hgm.nubati.net/rules/Chu.html . It highlights the moves, but does not allow you to actually move pieces around. This would be a rather trivial change, however.
This is the layout. All the new pieces moves are below it. I was curious if anyone could make this as a program for me. I do not need any AI at all.
2 player only. Just need a program I can place online. To play with my friend, who moved across country.(plus anyone else who may want to try it) We used to play every day. I would like the program, to show possible, legal moves. When each piece is clicked. Plus not allow illegal moves. That is all. I would be willing to pay someone to code this. I have been trying to learn for 7 months. Yet I'm lost. So all I can hope to do, is pay someone to help me out.
X's are where leapers can go.
Arrows are sliders.
Leapers may jump over the black, off board, areas to get to a free tile.