Here there's an interesting section concerning origins of the word "espresso" and seems to give credit to both theories (speed and pressure):
http://en.wikipedia.org/wiki/Espresso

It also says that in English both "espresso" and "expresso" are used, which makes me, by pure chance, not so wrong.

Also, it mentions that the "espresso" word, in reference to a coffee, was first used here in Italy at the beginning of last century with the first steam coffee machines. If so, it could only mean fast. The "expressely for you" idea is a bit inaccurate. Back then, they used to say "espressamente per te" ("Expressely for you) to mean "fast ("espressamente") and just for you ("per te")", but the word "espresso"/"espressamente" still meant "fast" and neither pressure nor "for you".

In any case, whatever. I was just curious.