Vegas 11 does a good job editing .ts files. I've had success with a tool for the Mac called Foxit Video Converter that will convert the .m2ts stream to .ts. I think DVDFab will do this on the PC itself but I've been running off an expired (read: free) version that has the conversion features disabled.
The rub so far has been that FoxIt downsamples (nicely, but downsamples nonetheless) the DTS audio to AC3.
The nice part is that you can import the .ts file and it map the video stream and the audio stream locked together with the audio channels assigned appropriately.
I'm using Vegas 11 Platinum, not Pro, so my output audio ends up being 5.1 PCM. Not generally problematic, but a space hog on BD-25s.
So the debits so far are:
1) Downsampled Audio
2) Recompressed video.
It all looks and sounds really good, but isn't the perfect-as-original stuff I've done with Womble and standard-def. I'm going to play with some other formats, such as converting to AVI instead of .TS and extracting the .DTS streams to WAV. Then, it's just a matter of getting the seventh and eighth channels to map an encode correctly back into the BR. Not sure if Vegas 11 handles that yet. Documentation on Vegas 11 is really bad for such a nice commercial product, so I'm learning as I go.
Still wish I could find a way to do this for a living. Both editing and teaching how to edit.