somewhere i heard the boxes save separate m2v and ac3 files when recording.
why cant you mux them into 1 big mpeg or vob.
if there is a size or time limit on vob or mpeg you can use mkv witch is an open format (that's why pirates like using the format when p2p sharing movies (also no license requirements)).
as it stands now when downloading via ttg it muxes the files into a tivo file and if there is a corruption the the download aborts.
if you can use an open format then if there is a corruption there is just a blip and av sync issue for a few seconds until the next block.
you can still encrypt the mkv file to protect the content for amazon purchases or if the channel protects the content.