What is this based on? Certainly there have been many studies. Also, to be clear, Acela is not HSR by that definition.
I can imagine many other places: Florida, then north to Atlanta and west to New Orleans, and then connecting to Texas. DC down to NC, then Atlanta, then connecting to Florida. Vancouver (with some international cooperation) to Seattle to Portland to the Bay Area, connecting to the rest of California. A Midwest network of St Louis, Kansas City, Indianapolis, Chicago, Milwaukee, Minneapolis-St. Paul, Detroit, Columbus, Cleveland, and Cincinnati, Pittsburgh (connecting to the east coast via Philadelphia), and north from Detroit to Toronto and Montreal. Las Vegas and Phoenix might want a connect to the California network.