Prevost didn't put slides into any coaches in early 2000's. My 2001 got slides from HWH. My slides have been problem free (as long as I keep adding power steering fluid to the reservoir).
Then Prevost quit making a 40' coaches. So that's likely why you'd have a hard time finding a 40' with Prevost slides.
Have you considered adjusting your driveway length to accommodate a 45' coach? Not really joking, as this would open up a plethora of choices. Your current parameters are going to make your search near impossible after waiting for one of these unique units to come up for sale.