Are there any dvr's or pvr software that will skip recording the commercials completly so as to save space in the first place? I'd love to regain the 25 to 30 percent of space that commercials take up.
Well, MythTV on my Gentoo box will, but that is a bit off topic, and anyway they are having some issues with providing a free guide for users.
No, but in my experience Video Redo will flag the commercials pretty accurately, then just cut the selected ranges and resave the video. I did this to a recording of the 49ers-Cards game last Monday (HD stream, TP format). Original was 24 gb, after editing out commercials it was 16 gb, so about 33%. If this is just for casual viewing, compress to mp4 and you get it down to what, maybe a 2 gb file...