[iampims]

There is also the basho fork of LevelDB (https://github.com/basho/leveldb) which adds a few nice things.

If you're interested in the internals of LevelDB, I strongly recommend watching this talk http://www.youtube.com/watch?v=vo88IdglU_8 (slides here https://speakerdeck.com/basho/optimizing-leveldb-for-perform...)