I gifted my old WWAN-less Mini to my father-in-law over the holidays when I found one on Dell Outlet with a WWAN port. I received it yesterday and spent the afternoon today getting a Dell Wireless 5520 AT&T card swapped over from my XPS 1330 just to try it out. Took me a little while to get the software configured as it would not allow me to unpack the install .msi that came with the XPS 1330. I just copied the drivers over from the XPS and let it run through the new hardware discovery, pointing it to the copied drivers when prompted. Install went smoothly from there. I configured it like a modem copying the settings over from the XPS and it worked great. I was getting 3.8mbps in my basement. I had to use the aerial/antenna from the WLAN card to test the WWAN card as the new mini only came with one antenna. Beats me why dell puts all the hardware for the WWAN in there and then leaves the antenna out. I will be ordering a larger drive, the US-Intl keyboard, bluetooth, and the WWAN antenna on Monday. We'll see how that goes.
My Mini 9:
Win 7 Ultimate, Runcore 64gb SSD, 2gb RAM, 5530 WWAN/GPS, US-Intl KB, BT, ext. Blu-ray