DRM is here to stay
Wow, 24 hours is a really short time. At least they should match what the rental companies (Blockbuster) do for new rentals (2-3 days). A week would be better.
I think their concern is that if you have the PPV for a long time in your DVR, you'll have more time to archive it, and that'll eat into their DVD sales revenue.
With DirecTV, one possible way to get around the DRM restrictions is to get a Hauppage HD PVR (I believe it will be released around May 1, 2008). The PVR uses the composite outputs, not HDMI. I think they call that the "analog hole" or something to that effect. In any case, I don't know if the quality of the HD recording on the Hauppage will be on par with the DirecTV HD DVR.
It'll be a matter of someone doing a few tests on a variety of HD channels (or PPV if that's your thing, I personally have never ordered movies PPV from cable/satellite. The rental store and/or DVD delivery by mail is similarly priced and doesn't have all the time restrictions of PPV).