This might not be hardware related, if you get a regular router you might consider a USB-pluggable/adaptable 3G/4G modem.
Kong builds [ http://www.desipro.de/ddwrt/ ] support the modules needed in-built. It requires a 8MB or 16MB flash, and one of a few Netgear or Linksys models.
Either way, with a little [extra] know-how, you can load these kernel modules on boot and try getting it to work that way. I've seen a thread addressing 3G/4G USB modems here at DD-WRT