As Rob mentioned, there are 3G/4G routers out there. One such vendor is Cradlepoint. You have to check Cradlepoint's compatibility list to make sure your USB modem will work with it.
As far as the statement about wireless versus wired for gaming, it is false to think wireless is not capable of supporting any gaming protocol. If you look at the amount of actual data being used by games, it is minuscule compared to other applications using network connectivity. The important need for games is low latency and a stable connection. What gets wireless a bum rap is due to the use of 2.4 GHz frequency space and all the ambient interference. Even when 2.4 GHz is used, there are wireless systems which can create a very stable wireless connection. And as Rob pointed out, using a cellular based Internet connection is probably more unstable than a WiFi setup.
As far as the statement about wireless versus wired for gaming, it is false to think wireless is not capable of supporting any gaming protocol. If you look at the amount of actual data being used by games, it is minuscule compared to other applications using network connectivity. The important need for games is low latency and a stable connection. What gets wireless a bum rap is due to the use of 2.4 GHz frequency space and all the ambient interference. Even when 2.4 GHz is used, there are wireless systems which can create a very stable wireless connection. And as Rob pointed out, using a cellular based Internet connection is probably more unstable than a WiFi setup.