i think full blown ORM-style is the wrong abstraction, at least for now. until the abstractions are good enough, staying close to the metal is a good idea. also querying is easy (there's not a lot of options), but keeping multiple indexes updated and partitioning them etc. is where the fun begins.

for my own needs, i've started building a thin (transparent) abstraction layer for cassandra . take a look here for a code example: http://github.com/enki/tragedy