The LTE-enabled version of the new Nexus 7 is now available from Google Play. The device will set you back $349, which includes a SIM for T-Mobile. The carrier offers mobile data (tablet) plans starting at $20 / month for 500MB of high-speed data, all the way up to 10.5GB high-speed data for $70 / month. Once you hit your cap, you'll slow down to 2G speeds.
The new Nexus 7 model supports the following cellular bands: