The manufacturers of the Wikipad gaming tablet have announced plans to release a controller accessory compatible with other brands of mobile devices, Gamevice. The controller, which can expand or contract to fit various tablet designs, features dual analog sticks, two pairs of shoulder buttons, four face buttons and a directional pad. Wikipad is currently working on versions compatible with Android and Windows 8 mobile devices and hopes to announce support for "other important OS systems" soon.
Yeah, they'd better get on that. Seems like you'd be shooting yourself in the foot a bit to release an accessory like this without including iOS in the range. Still, if you've been eying the Wikipad's controller design and feel your current tablet is a bit sad without something of the sort clamped to it, this could be an option.