It's already a bitch to lug around your 3DS with that big ol' Circle Pad Pro attached, so why would you want to add a PS1 controller to that? Oh, maybe because it's fu*king pimp!
Yeah, sorry. I know it's not that cool. Still, this Japanese mod of the slide pad attachment to use a controller to play Monster Hunter 3G on the 3DS is pretty crafty. It's also nice that the controller can be unplugged for easy transport. I have a feeling that this guy's life is going to be much easier when MonHun hits the Vita.