I was so tired of not having at least basic controls for a mecanim compatible rig that I finally broke down and made a really basic set of controls for one of the Mecanim default characters.
He's nothing that special: FK arms + IK legs, no special face/hand controls or fiddly bits. You'll still have to directly animate on the bones for hand and face animations, but at least doing basic blocking and pose-matching won't take so long now :D
One of the benefits of this being really simple is that I think the fbx should work a lot of places (please let me know if I'm wrong), so I have an MB and and FBX file you can download and use.
Other than that, he's really just the default mecanim body -- skinning and all. You shouldn't have any trouble bringing him in engine as long as you remember to turn on animation export (and baking) in the fbx export dialog.
MB file for Maya
FBX file for Maya and Everything Else