I was messing around in the testing arena to see if any of the new animals have the potential for necrotic bites to help create fleshless soldiers, and I came across the Gila Monster. Their only attack is a weak bite, incapable of opening arteries in a naked adult dwarfs throat, and seemingly incapable of removing fingers and toes. Although they're so weak that wild gilas introduced to dwarves would doubtlessly be stomped to death, with a no-exotics type mod fixing the dungeonmaster issue, tamed Gilas could be put in a quantum-pasture and provoked into biting a dwarf. With a clutch size of 2-12 and a maturation rate of one year, it could also prove possible to produce enough wild gilas.
The venom causes the targeted body part to rot (in the skin, fat and muscle) and swell with blood, but does not cause death by suffocation like most snakebites will, even when the targeted part is the upper body, throat or head. This leads me to believe that gila bites will produce a manageable infection giving your surgeon cause to remove flesh.
The only problem so far ; gilas don't inject any poison. On further testing, it seems that many of the new venomous creatures such as adders and bushmasters don't inject any venom, only their giant and -man counterparts do. I'm assuming this is a bug in the raws, and if anyone knows of a quick-fix that'd get the venom flowing again, I'll start a science outpost to capture some gilas and test out the practical applications of using gilas for painproofing one's soldiers.