How much current through V_in and GND pins?

Far-seeker:

tmmlrd:
Does someone know if an extension cable for that "square" USB connector (don't know the name) exists?

You mean something like this panel mount, Female B to Male B, USB extension cable?

Right! This is exactly what I had in mind!
Many thanks, I'll see if I find something similar in Europe... otherwise I'll try ordering oversea. I know it would take 3-4 weeks, but could still be compatible with my development time (delivery for Crhsitmas! :P).
Thanks to all.