It is rare to get more than 30% off actual MSRP list price on any new unit.
But then there are jacked-up MSRPs and older units still sitting on dealer lots to skew that statement.
Be careful of discounts above 30%...and be careful of buying just on price. When you can actually get confirmed quotes on exactly the same unit/options, then you can begin to balance things such as distance/time to pick it up, warranty work away from selling dealer, and other such mundane items that may come back to haunt you.
Have you checked into any used units in the same floorplan? RVtrader.com and pplmotorhomes.com are two places to look for market values.
'05 36TK3 Mobile Suites
'10 F450 new to me
'09 F450 Lariat 4x4--died