Amazon.com: 4G LTE USB WiFi Modem, Portable 4G Router with SIM Card Slot, High Speed 300Mbps, Portable Travel Hotspot Mini Router, Unlocked 4G Dongle, Up to 10 Users : Electronics
This dirt cheap 4G LTE modem on a USB stick can be hacked to run mainline Linux - Liliputing
DWM-311 4G LTE Cat.4 M2M VPN Modem | D-Link UK
Proxicast: EtherLINQ 4G/LTE SIM Router with WiFi, VPN, Firewall