It's no rocket science. With some research, I could point out the resistors that need change. (there's pics, we know the opamps...)
I would not describe myself as anything other than a bodger but I've opened my own MT to poke around the boards and despite knowing the pin outs of the opamps I still couldn't be certain of the resistors in the feedback loop to give the gain. Personally I would prefer to completely bypass the opamp and go straight to the ADC if possible, any rocket scientist out there going to give anyclues?
Just someone with SMD-skills and some business sense?
I think that "business sense" may be the biggest stumbling point, despite many on TS having MT's I doubt there would be a huge market for this very fiddly work, not to mention needing to charge enough to cover any "accidents" that may occur doing this kind of work.
It would also appear that many people are just using the MT as a bit-bucket so line input mods really wouldn't interest them.
I really think a solution to this is more likely to come from people tinkering around rather than those who could sell on their expertise. After all Oade has decided not to sell this mod and I think from previous posts Bussman planned on doing something but ended up selling his MT to concentrate on the R4.
Of course the other factor is M-Audio may release a revised version MT2? since I already think they have altered the component design without telling anyone.
Maybe install a slightkly bigger Li-Ion pack? (see thread about battery mod)
I think this is the most plausable mod at the minute since bigger mAh batteries are coming along all the time with smaller form factors for other devices like the ipod, so eventually we'll get one to fit even if it means removing the ?voltage regulation circuit on the original battery.