DB81's were higher rib guns in a time when most shooters were still shooting low ribs. By today's standards, the ribs are quite modest. The rib is a fixed height, so you adjust your comb and go from there.
With a lower rib than a TMX, which was greeted with acclaim, the rib height issue is today really a non issue. Certainly lower than the more recent Pgun adjustable rib options. Consider them ahead of their time.
Really DB81's are MX8's with higher fixed ribs. If you like a higher fixed rib top single/combo, you may well love them.
My understanding isthat they were designed for Dan Bonillas, who had been shooting a MX3 Special (a relatively high rib as well), after spending time with the DB81, he eventually went back to the MX3 Special - which makes sense. If you are a successful world class shooter, why change your equipment?
A model no longer offered in the catalog, although I assume still available for custom order, it's not likely that you'll find the factory sponsored level shooters competing with them. Manufacturers want their representatives shooting models that 'ordinary' shooters can see and order. Don't let that throw you though, there are lots of models that are wonderful but not still available (TM1 and KX5 come to mind). When you read posts about the 'high' rib on a DB81, look at current trap offerings by the major competition gun manufacturers - and chuckle...
Try one if you can, you may well feel like it was designed for you. Good luck!
ps.
If you find one you like (or want to try a DB81 o/u barrel on an MX), let me know, I've got a Seitz modified DB81 31.5" o/u which I'll part with.