Could ThinkGeek's iCade become more than an April Fool's joke?
The biggest problem right for these kinds of products is that can only work with a jailbroken iPhone. Otherwise, the API Apple added in iPhone OS 3.0 forces companies who want to make iPhone and iPod touch accessories to pay a potentially prohibitive licensing fee to join Apple’s “Made for iPod” program. At the same time, these companies would also need to get access to the necessary chips that will authorize their accessories to connect to the Apple devices.
While these roadblocks have limited the development of such products in the past, it is possible that with the increased gaming possibilities of the larger screen iPad there will be a greater demand for such accessories. In fact, Apple themselves may have been looking into this idea ever since they filed a patent for a gaming accessory in 2008.