Richard Overy from what I have learned in recent months is a good source for numbers. You'll recall I was first introduced to this author by my "go-around" with Full Monty. We covered all of this ground in several exchanges here-
http://www.kampfgruppe.us/showthread.php?t=4396
in particular, page 5, post #43.
a good estimate is 16.13 million were left in all capacities of the Soviet military in May of 1945. That's all branches. I don't have the breakdowns, but I imagine you could take an educated guess.