I wonder if they will send you a new one if they deem the part not an easy fix, or if they will just swap out the mobo. Also, I haven't gotten my mini yet, but the fact that it has 3 USB ports is just crazy! On my desktop, sure, I use like 8 or 9 ports with all the peripherals I have (printer, wacom, keyboard, extra mouse, other wacom, logitech NuLooq, 2 external hard drives, various USB keys, scanner, and the list goes on). But on my full size laptop, I only have 2 ports (damn you apple!) and it hasn't really been much of a nuisance yet, except when I attach an external hard drive that needs a Y connector, that is truly a pain!
Good luck with your replacement though!