No. It's not a fantasy. The Nokia N900 was amazing.
It functioned as a phone with a touchscreen to deliver the experience that had now become the dominant one.
But also, by sliding up the screen, it had a fully featured keyboard, and essentially transmogrified into a "pc that fits into your pocket".
So you could with a one handed push go from the touchscreen-only experience back to edit documents by using a combination of the keyboard and the touchscreen (with a stylus if neccessary).
I stopped using it because it lost software support and then the touchscreen stopped working, but I have it sitting here at my desk.
It functioned as a phone with a touchscreen to deliver the experience that had now become the dominant one.
But also, by sliding up the screen, it had a fully featured keyboard, and essentially transmogrified into a "pc that fits into your pocket".
So you could with a one handed push go from the touchscreen-only experience back to edit documents by using a combination of the keyboard and the touchscreen (with a stylus if neccessary).
I stopped using it because it lost software support and then the touchscreen stopped working, but I have it sitting here at my desk.
Every phone I have used since has been worse.