We currently have 30 locations throughout the United States that have a cable or DSL internet service connected to a Cisco 1721 or 1811 router. This router is configured to create a VPN connection back to our corporate office. We have lost our primary internet connection for up to a week at a branch. We would like to come up with a Cisco router that can use a Sprint, Verizon, or AT&T 3G modem that we could overnight to a branch so they could have internet connectivity until their main service is restored. Any suggestions?