My company manufactures a DVR that meets all of your criteria. The company is called RTS Sentry, and the web address is rtssentryDOTcom. The product is strong and the prices are very competitive in the mid-range PC based market.
Our Echelon system is what you are looking for (30fps on all 16 channels @ CIF, POS integration to Ruby, Passport, Aloha, and more).
Reply here or send a private message if you want more info. I really think we can help you out!