Hey, thanks! That means alot to me. :)

Well, here are parts where the bodies differ in terms of the actual skeleton:

Simon - has right and left buttocks similar to the other G2 models and Daz Millenium figures. Simon also has a waist in addition to the abdomen.

James Casual - is a standard Poser Propack kind of rig, with no buttocks, only thighs and no waist, only an abdomen.

My toon character has seperate bones for the upper and lower teeth/gums, a waist 1 and waist 2 (I find it bends better on this particular figure), and right and left buttocks'.  

Also, both the G2 male and James Casual have dials for things like hand spread and grip, which are often used in these poses. While they simply call for the joints to take certain positions, the hands of my model have not been tweaked and by all rights, should have turned out an awful mess when the pose was applied.  The fact it did not was no testament to my rig, as I tried the same mesh in Poser 6 to little joy.