Medicare
I don't think Medicare will cover a tummy tuck. They will cover a panniculectomy to remove excess stomach skin if it's medically necessary. Just like most other insurance companies.
Please note: I AM NOT A DOCTOR. If you want medical advice, talk to your doctor. Whatever I post, there is probably some surgeon or other health care provider somewhere that disagrees with me. If you want to know what your surgeon thinks, then ask him or her. Check out my blog.
Medicare is VERY reluctant to cover any sort of plastics unless you can demonstrate medical necessity. If you have any persistent rashes, boils, yeast infections, etc., get them documented by your PCP. Your plastic surgeon, if he accepts Medicare at all, should be able to tell you whether Medicare will cover in your particular situation once he examines you.