This is the first of my FIRST!!(I think) posts, where I trot out stuff I think was invented by me. I'm sure somebody out there on the internets will prove me wrong in short order.
Here's a sliding keyboard phone concept done for a bizdev guy in late 1998 for Qualcomm's QCP(Consumer Products) division. I used to dig the two-way RIM pagers IT guys rocked, and loved my Palm Pilot. This was an attempt to combine a pager-like form factor with voice & PDA functionality. Notice the monochrome display common to phones and PDA's of the era. I don't know why the wired earbud mike was rendered small enough to fall into your ear canal though.
A closeup of the fuzzy, cheezy sample UI shown above. As I remember, the product was aimed at the enterprise, so in this example use-case I attempted to portray the indispensable mobile comm unit for the hip cable-guy of the near future. Note the stock prices on the right frame of the display, I miss the pre dot-com crash stock market..