Comment Not new (Score 2, Interesting) 135
I work in the cellular industry, and this isn't new, other than being kinda small like the MiFi. If you wanted WiFi with a cellular backhaul in your car, you could have gotten that from Linksys, Cradlepoint, or JBM (now Sixnet) and others anytime in the last few years that I've been in this industry, probably much longer. If you were content to get an Ethernet connection and add your own WiFi hotspot, the list expands to Airlink, Bluetree, Digi, etc. And that's just off the top of my head.
Of course, geeks will always find a way. A friend of mine in high school created a dash-controllable MP3 stereo system for his car in 1999. He had an entire PC running Linux in the trunk and the display was re-purposed from a home security system. But that's not exactly a consumer-friendly setup.