RW Racing i think it was used to do these back in the day. They were sold for both the long and short wheelbase chassis.
I however brought the last stock remenants of these a good few years back from them as a job lot - i was told they looked everywhere to find them all so i doubt they have any now but you never know.
Im pretty sure one or two other companies made them back in the early 90's but havent seen any others in years.
Good luck with the search
