ThinkGeek has announced that its iCade gaming cabinet for the iPad and iPad 2 is now available. Initially announced as an April Fool’s Day joke in 2010, the iCade was built in partnership with ION Audio, and features a fully-functional gamepad with a retro-style arcade stick and buttons, a built-in cradle for the iPad, Bluetooth for connection to the device, and the ability to run off two AA batteries. Currently, the iCade is compatible with…