Mobile device gamepads: have you used any? Can you recommend one?

I really want hardware controls for gaming on my Galaxy Nexus. I understand almost any Bluetooth gamepad works with Android but the problem is having the controller recognized in games. I noticed some gamepad manufacturers are partnering with game developers to support the controllers natively but from what I understand this would be specific to one or two models of gamepads, not hardware controls in general.

I also don't want a big bulky controller to lug around with my phone; the Ringbow on kickstarter looks pretty promising but because it's lacking buttons I'd need a second one or use it in conjunction with on-screen touch controls.

Regardless, are there any gamepads that people would recommend or methods to get existing mobile gamepads to work with existing games?