A Linksys router that used a Vodafone Mobile Connect Card 3G for UMTS backhaul, and one of the hardware testing projects I spent quite some time dealing with - to the extent of having one of the early testing samples.
There was a somewhat ridiculous misconception that it was limited to 5 users, but it's not - that was initially just a reference figure for the number of business users (running standard Office applications) that can share the standard UMTS 384/64Kbps rate without noticing any performance degradation. Outlook alone will generate far more traffic than your average browsing session, and tends to clog up any connection.
The really sad bit is that these days hardware is intentionally crippled to enforce a 5-user limit...
Resources:
- Coova, an interesting hotspot management solution with a WISPr-compliant Firefox extension for automatic login.
- Linksys GPL Code Center
- First Press Mention (Spanish launch)
- Engadget
- Local news