ok, it's been discontinued for what, 5 years? it's a fabulous device -- but here's where i think improvements could be (or could have been made) -- well, had development not stopped.
- faster proc, more memory.
- electroluminescent backlit display.
- power slider switch (immediate off / and hold switch).
- how 'bout actual credit card slim (smart card interface?).
ok that last one, i'm just dreaming stuff up. but i already have the smart card interface in my laptop. the electronics could be made wafer thin, even the screen. you'd have to make the battery sliver thin, and of course - rechargeable.
all the other points are certainly possible, the backlit would be nice. for the most part i think cell phones can offer what this device does -- but it will be years until we get something trim & functional. emphasis on trim.