I finally got a chance to look at this carefully last night--I got the DX set and both Aeon sculpts as well--and what marlin shows in his pictures is precisely what I got. The Aeon sculpts actually have a better skin tone IMO, but the huge eyes are distracting. My cab driver also has the blush makeup look on the Rainman painted head, which is also a bit distracting. The Rainman soldier sculpt is the best painted of the bunch.
Regarding the mod to put the torso on, I used one of the recent KO narrow shoulder TT's and not a stock TTM-21, but the process should essentially be the same:
I found that the easiest way to handle this mod was to pry apart the TT abdomen, but leave one half of it in place, so that it is still propping up the little plastic tab under the spring. Then, you could use that piece to lift the tab up a bit, while sliding one half of the Rainman chest piece under it on the other side. Then, take the original piece out, put the arms and neck piece where they have to go, and use the RM piece in place to pry the spring up to put the other piece in place. I did find, however, that the screws that were in my original body held well in the lower holes in RM's chest, but didn't screw in very well in the upper holes. Perhaps because of that, there is a gap in his neck. If I knew I would keep him on this body permanently, I would glue it in place, but the cabbie head seems to sit low in relation to the shoulders somehow, so I might try a different body.
The mod actually wasn't that hard once I decided to keep the original abdomen piece in place, but the spring is extremely tight, meaning you have to put some real pressure on the Rainman pieces. Knowing that this is an expensive "art doll," most of us probably have an aversion to doing that, but there's really no way around it.