It looks a lot like a Royal Enfield Thunderbird.
Unfortunately it is using the single downtube frame rather than the new CGT frame.
I also have to wonder if 600cc is going to do the job?
RE has a history of making less horsepower than most modern motorcycles get out of their engines and in the USA on the open roads, horsepower is needed.
I'm not talking about 70 horsepower out of a 600cc engine but at least 55 would be required to cruise along with the cages at 75-80 mph on the interstates.
These 250 hp cages don't slow down on the uphill sections of the roads here so the engine has to have some extra power for these conditions.
On a positive note, I do like vertical twins like the one in the picture shows.