I can see one possible solution to the 942 vs MPEG-4 problem... a future MPEG-4 capable STB that connects to the 942 via firewire and, in conjunction with a firmware update, uses the 942 as nothing more than a slave drive (the new STB would encrypt data before sending it to the drive, and decrypt it after reading it).
After all, the drive accounts for the lion's share of a DVR's cost. It wouldn't be quite as compact and neat as a new DVR, but I don't see why it wouldn't work. The only snag might be an inability to preserve content saved on the 942 prior to adding the new box (unless the decryption key used by the 942 can be recovered and imported into the new box)... though I guess they'd probably come up with a kludge, like leaving the 942-era content intact, but only being able to view it by connecting the 942 to the TV as a second video source and letting the 942 itself play it.