Don't see why it would be a problem for a these companies to make a device such as the ASUS WL-330NUL or the Kanex Myspot ... especially based on what I purchased recently in Asia -- a USB Stick that has a 4G/3G/2G Cellular Data Modem with a NAT/FW/Router and provides a WiFi Hotspot also all built into a USB stick (for those interested google E355)
Hopefully this category matures fast as they apparently do have the chip/chipsets to build this functionality now.