Latest Toughbook experiments brought me into 3G card swapping thing. I have CF-53, which works perfectly with integrated 3G (Sony Ericsson miniPCI module) and then I have CF-C2 with integrated Gobi3000, which is total crap from Linux point of view. So, latest is that I swapped Sony Ericsson module from CF-53 to CF-C2 and now my favourite laptop (Toughbook CF-C2) and now it has 8GB RAM, working 3G connection and working touch screen.
All running with secure Ubuntu 13.04.
I have also other measures on stock to enable integrated 3G on Toughbooks. So, make sure Panasonic gets your opinion about using Gobi and Windows. Our governmental clients cannot use Windows for security reasons and every unit we ship, we do this installation of Linux and enabling 3G and security.