Has anyone made the original DOOM green armor marine, or have a soldier actor that is close enough to fit the role?

I don't, but "Barrels of Doom" are on developer's todo list ! Coming in Voxatron 0.2

By the way, do you know of DooM Voxel Project ? Their vodels are too high resolution for Voxatron, but they can be used as a reference.
http://www.teamhellspawn.com/voxels.htm