HalfPawn: As far as I know it is only played here. I made reference to it on a Chess variants Capablanca comments page, but the game has yet to get very widely known. It's only a couple of years old and it so similiar to the other four games of this type that it might be sometime before any of them become widely played. Gothic Chess would seem to have the most current players, but things change over time.
http://www.chessvariants.org/large.dir/capablanca.html

For some reason it's hard for the larger board variants to get many players. It's probably do to the lack of on hand playing equipment. If I ever get around to it, I'm going to make some larger Chess boards and some extra pieces. I'll still the problem of finding someone to play though. :(
That's why I play here. Regular Chess is tough enough for most people. These larger games with a couple extra unfamiliar pieces thrown in are just too much for a lot of people it seems. I like the games and think they're fun and challenging to play.