Once upon a previous century I tested a laptop with a built-in printer for an article I wrote for a magazine. Paper was fed through a slit underneath the keyboard, ink was dribbled on it from a microscopically small ink cartridge and in only half a minute it worked its way through a single A4 sheet.

It was made by Canon under the name Notejet [1]. It did not come with a built-in desk though.

[1] http://laptop.pics/canon-notejet/