The Kiano 4 is a sliding keyboard for the iPhone. It has a built-in battery that has about 5 hours of typing and 30 hours of standby. It uses standard Bluetooth connectivity to operate. The Kiano online store has it in both black or white color. It’s listed price is $99 US.
Seems like a cool device for people who want the tactile feel of the keyboard. But I’m not sure how many people are willing to accept 78 grams of additional weight to carry around making their phone a bit bulkier.