I would get some sonic stickers and decal the heck out of it.
My sister has a silhouette machine. It's like a printer, but it cuts shapes out of paper. I might have her cut out a sega logo and/or the three oval game gear logo for me and stick those on.
Also, I don't have any game gear sonic games

I tried them through sonic adventure dx, but the only one I liked was tail's adventure.