But not like this, this is too long and I don't think one will have a pleasant typing experience with this.
I thought about this one for a few minutes, but I can't think of a good way to integrate a keyboard in a smartphone case, that will give you the experience of a blackberry or similar.
The slide-out ones that you could use in horizontal orientation are probably the best way I know of, but I wish something similar could be feasible in vertical orientation.
EDIT: I just realised that the coolest way would be, if the phone display is only as large as the current phones minus the keyboard, and then a physical keyboard beneath it. The phone would be physically as large as the phones today and you would have a superior typing experience. Only problem would be watching videos or images which are all either 16:9 or 21:9 (or vice versa). And I'd personally trade the screen size for a physical keyboard