Utica- Misch turned down the 5th round to reenter college, and was a 7th rounder in '03. In his debut MLB season in '07, his fastball was consistently 87.3 MPH and reached 92, according to PitchFX on Fan Graphs.
A good example of a crafty lefty would be Rowdy Hardy. Hardy was a non-drafted free agent sign and is currently in AAA.
To get back to the OP, you are on the right path, and you seem to have a very talented player on your hands.