I love your creation! The circle screen is a great idea and your theory behind it makes sense. I wish I could try that in real life to see if using a circular screen works. Maybe if I draw a circle on one of my DS screens and color the outside with a black marker, I'll get an idea of how it would work out. The touch pads are cool too. They'd probably work similar to the iPod's sensor wheel. I support the flip lid idea because I like to keep my screens in perfect condition. The subwoofer is a welcomed addition, since that hasn't been put in a handheld before. And the bass sounds that it outputs could cause an unintentional rumble, thus giving you an innovative built-in rumble pack too ^_^
The only thing I might suggest is moving the left touch pad down on the left side of the D-Pad. That might feel better. I've held my hands up against the screen though and your configuration appears to work fine also.
I also like how your battery indicator is much more specific about displaying exactly how much battery power is left. I would only suggest replacing the red indicator color with just black so as to upkeep the black and green theme of Xbox.
This is a great job for being your very first creation built from 100% scratch. I am proud of you.
