I'm using Haskell + CouchDB. The bindings are simple enough that I've been able to hack fixes for them pretty easily, and just as importantly, Haskell's GADTs

I'm using Haskell + CouchDB. The bindings are simple enough that I've been able to hack fixes for them pretty easily, and just as importantly, Haskell's GADTs are much easier to translate into JSON than they are into SQL rows (at least I thought so). Turning around, you can spit JSON back up at the web layer after some mapping, filtering and processing, so it's not as if you'd wasted effort by writing JSON instances for your data.