Have you read the recent post about Casio PX330 ? This is their newest model that is generating a lot of buzz even among the pros for only a few hundreds bucks. And it has the fully weighted piano action IIRC.
http://www.synthzone.com/ubbs/Forum37/HTML/020094.html

Casio is normally mediocre but looking at the new model, this is a different animal that rivals the best digital piano out there that are much more expensive. And it has drums, rythms, etc. Looks like it fits your needs to a tee

Should be easy to find probably in Guitar Center where they have generous return policy.