The folks at NBA Draft.net pretty much spend their lives speculating on that very subject and have projected three Michigan players in the 2013 draft.
Glenn Robinson, Fr., SF, #15 to Atlanta
Trey Burke, So., PG, #25 to San Antonio
Tim Hardaway Jr., Jr., SG, #31 to Washington
I'm a little surprised Burke and Hardaway aren't rated higher, particularly Burke. From a selfish perspective, they would be less likely to leave.