The picture of Nyko's Zoom Case for the DSi says it all, no?
Nicking a bright idea from Brando, Nyko's Zoom Case utterly obliterates portability and reason in exchange for 8x of zoomglory—because we all know zoom is what's missing from the DSi's 640x460 camera.
You can detach the lens from the Zoom Case. You know, if for some reason you wanted to. Sadly, Nyko hasn't given us a price or date for this marvelous kit of awesome, but whenever it comes out, it's not soon enough—there are celebrities to be stalked, upskirts to be snapped, out there, waiting.