We tried and successfully installed Mountain Lion on a MacBook Core 2 duo non supported based on Apple's list.
We have used a procedure similar to the one described by Jamie Cruickshank and used for the Mac Pro 2006.
To be mentioned, with the lack of drivers (GM 3100), there is no accelerated graphics. However, we will try to find some work around, maybe used the one from Lion. If it works we will publish the procedure in details.
