well, you could open it up yourself and put some sort of insulation around the joystick base to keep it from shaking. you can refer to gp32emu.com's FAQ section to get step by step procedures. refer to the "Dying your gp32" FAQ (it tells you how to open it...and even change the color of your gp32 if you want. It is very simple for non-flu users but for FLU gp32 owners, it requires soldering. Also, there is a great guide there to make your own light for the gp32 (for the non-flu users). I have opened up mine before because the on/off light switch came un-glued to the plastic shell.
That website is www.gp32emu.com if your interested