Say 16inch so easy swap. If there was enough demand I'm sure somebody would make 'em, I really want some but I aint gonna spend £1600 and change brakes etc.
...my point is if there is enough demand could they?
Don't ask TVR Engineering for help. They want you to change your hubs and help them dispose of the several hundred unwanted 16" 5 stud spiders sitting in their parts department.