There are, but I'm not sufficiently familiar with the market to make a recommendation. The last time I looked, several manufacturers had pre/pros in and out. Yamaha, Onkyo, Denon, Marantz, all had one, but I don't know about anything <US$500. The two big contenders for me were Emotiva UMC-1 and the Outlaw.
The main problem with the NAD is that you'll want to add a sub eventually, but there are products specifically for that sort of thing (ICBM-1, etc.).