In adding slightly more bulk to the born-svelte iPhone 4, the Mini Key does feature illuminated keys and connects to the phone via Bluetooth, while also including a microUSB port for charging to make up for the covered dock connector. Since there is no extended battery in the Mini Key's hard-shell case, expect that iPhone of yours to need a few more trips to the nearest AC outlet.
Hopefully the Mini Key can be cleaned up a bit before it's released, as the build quality looks like it could be improved, but at an expected price of $60, the thing still looks like a bargain. Maybe this is just the accessory to get other companies interested in physical keyboards for the iPhone, because I would love to see something that could maybe expand into a fuller-size keyboard or even something that uses the magnetic attachment like the underrated HTC Advantage from a few years back.
[Engadget Spanish via Engadget]