This is the first 3G portable router.
LevelOne 3G MobilSpot Portable Wireless HotSpot (WBR-3800) by CP Technologies.
Putt your 3G sim card into the router’s CardBus or USB interfaces and you’ve got an instant portable network for sharing to any 802.11b/g WiFi or Ethernet device. A 10/100Mbps WAN jack lets it double as your home router with auto-switching 3G backup for those of you with particularly troublesome DSL/Cable providers. The device measures 129 x 124 x 32mm (which isn’t that small) but costs a reasonable $149.