There are cities within distances where it would make sense in several regions, but the speeds would be terrible because infrastructure is not up to the task (example: 300 miles in 7 hours 45 minutes). The rails don't support high speed service, there is no electrification, and the rails themselves are owned by freight companies. If the time was productive, you might get some small number of people to take it, but the excruciating slowness wouldn't appeal to many people.

What I have heard is that the sweet spot for high-speed rail travel in the US is to place major stations about 300 miles (500 km) apart. So running from Texas to Minnesota up the middle of the country you'd have 6 or 7 major stations. Travelling East-West from New York to Los Angeles, you'd have 11 or 12 major stations.

The only viable (and still not funded) project is the Southeast Corridor project, from Washington DC to Atlanta Georgia. Top speed is likely to be about 110 mph (180 kph). Average speed will be lower because the passenger trains will always be held up by slower freight trains (no dedicated tracks, like the TGV has)