I am sorry to hear about your 5D II. I had a
similar situation with 10D long time ago.
Marcus is absolutely right on this. The vertical
grip shutter button worked with no problem in
my case. I ordered parts from Canon and did
replace shutter button and it worked fine. It
involves soldering four small connections right
under the shutter after taking apart outer
shells of the body. My 10D still works, 40D is
getting there, 5D III is too young. IMHO it was
not hard and part was cheap (order two if you
are concerned). Good luck.