Hi GZers,
Has anyone heard of any products that could provide a mobile WiFi Hotspot that uses a 3G mobile connection for data. It also really needs to be able to support say 16 users/connections (They will be low traffic volumes), and it really needs a simple  firewall that can be set to block access to all but a nominated list of sites.

I am looking for this to set up a portable classroom/training venue.  

I found a few products that take a 3G card or USB modem, but none of them had the ability to whitelist what sites can be accessed. 

Any clues?