Draytek might be worth a look.
The Vigor 2800, 3100 and 2910 now support the addition of an optional 3.5G USB modem, providing high-speed Internet connectivity over the latest generation of cellular networks. Several UK networks already provide HSDPA data at speeds of 1.8Mb/s up to 7.2Mb/s (depending on network and modem), meaning that you can get broadband speed without a fixed line.
h**p://www.draytek.co.uk/products/vigor2820.html
h**p://www.dsl-warehouse.co.uk/product.asp?pr=VIGOR2820&gclid=CJOnkZWX3pQCFQyvQwodEGSmSQ