I'd like to share my idea for making a sort of finger handle, for the GameBoy Micro. Great for us with long boney fingers, having a thing for small electronic devices.
It only adds a few millimeters of thickness to the Micro, in return you'll get great control and never drop it again. (Can't even throw it in rage)
It dosen't get in the way of any functions of the Micro, and you could make one for the left, the right or one for each side. I found that one on the right side is sufficient for me.
You may have to try a few times, to get it just right.
Duct tape (5 cm. wide)
Start off with a 10 cm. piece of duct tape (yes, the handymans secret weapon), maybe even in the color of your Micros backside.
NOT too tight, you don't want your finger to be stuck, when the gaming gets hot, and your finger gets fat.
Cut off any excess if needed.
...and still very portable.