For the record, Mesa is not discontinuing production of the Road King, GC just isn't stocking them anymore. I'm sure they'll still be able to order them, but they won't have them on the floor any more.
The discounts are approved by Mesa in order for GC to clear their remaining stock (or so I was told by the guitar dept. manager when I bought mine).
As far as the 50-30-20-mile bit (or whatever it is), that's got to be a GC policy and not a Mesa one, because here in Indy there are four music stores within three city blocks of each other (GC, Sam Ash, and two independants) and both GC and one of the inependants are authorized Mesa dealers.