The Philips DSR7000 and Hughes HDVR2 are internally identical dual-tuner DirecTV/TiVo units. You're not going to find much else on the market at this point in time, though Samsung is rumored to have one coming out this summer.
One option to consider would be a new-in-box unit which has been upgraded with additional storage capacity. For example, long-time TiVo upgrade house WeaKnees (
http://www.weaknees.com) offers new DSR7k and HDVR2 units with 105, 140, 210, or 240 hours of storage.
The only pitfall, whether the TiVo has been upgraded or is factory-spec, is heat. Make sure the unit has adequate ventilation, and don't rack it directly above the 7x200W amp. :) One common trick is to add large rubber stick-on feet (inch-thick pyramids work well) to the underside of the unit to increase airflow.
Hope this helps.