It wouldnt surprise me that US wants to do this route. Could a A333 do this route? According to airliners.net the A333 w/ P&W engines has a range of 4550miles. According to great circle mapper its 4565miles to LAS from LGW. They need the A332 or A350 to do this. I can see LAS-CLT-LGW. Can a 767-200ER do LAS-LGW?
In my opinion US needs the A332, or a 763ER. If this were going to be a route expect it to be weekends only or a Mon, Wed, Fri, flights.