@4wd: totally FWIW...
I've never used it, but I'd venture a guess that avidemux uses code from DGIndex that's pretty much the std for that sort of thing, used in all sorts of video apps & ft ends. Reason I mention it is you might well be able to do the same thing, without having the restriction of writable media. Since you use it you'd be the best judge of course, whether or not you could incorporate DGIndex d2v files in your avidemux projects. There's also a version for avc streams if that's of any interest.
RE: V/Dub... originally mpg2 codecs were all payware, & not necessarily cheap - then import became a non-issue pairing DGIndex & AviSynth. With Avisynth you can do tons of stuff not possible anywhere else - loads of pros use it - & combined with DGIndex mpg2 import just isn't/wasn't necessary... in fact almost any native import is inferior to the DGIndex methods. Loads of folks prefer to get mpg2 into apps like Prem Pro that way. Only with version 7 did Vegas begin to import mpg2 with quality & performance approaching DGindex on the time line [Vegas requires an extra step, either frameserving from V/Dub or using VFAPI on your .avs file to create a fake avi]
Outputting mpg2 is IMHO best handled with payware like TMPGEnc, CCE, ProCoder, MainConcept code etc, though there are a couple of free alternatives: Qenc & HCenc. V/Dub can either frame-serve to your encoding software, or there are ft ends that handle all of it for you, often incorporating AviSynth, DGIndex, V/Dub, HCenc etc.
Finally, and again if it's of interest, several apps including DGIndex can strip out the audio & video files from a VOB set. PGCDemux is another I often use. TMPGEnc also includes very good muxing in it's Mpeg Tools section [I *believe* everything but the mpg2 encoding is free]. Many programs will only import VOBs, .m2v mpg2 video streams, or muxed mpg mpg2 files, so if you need to convert without re-encoding it's not that much of a hassle.