Arthur Whitney seems to have been developing this stuff pretty steadily. There's a sparse-but-quite-informative website at http://kparc.com/ where you could follow the development of the K5 and K6 dialects. It's been pretty quiet the last year or so, but there was a comment on HN a month or two back which suggests that K7 could be on its way.

For playing around with the basic constructs, https://github.com/JohnEarnest/ok is nice (and itself pleasingly concise). Currently targeting the K6 dialect, I think. It doesn't really have any of the "database" side of things, though.