I just got one of those free T-Mobile N-Gage QDs on Monday. The website did not mention this, and neither did the chick on the phone when I called up and ordered, but there was a $50 rebate form in the box with it, too. So, not only did I get it without paying a dime, but it looks like Nokia is going to send me $50, too!
Haven't tried MAME yet, I'm still fighting my Bluetooth connection.