I assume you're talking about the really pricey vintage M-75 Aristocrats. Well, they really aren't the same construction as a Gibson Les Paul. Although shaped like an LP, the Aristocrat is a small hollow body--quite a rarity for American guitars. The closest equivalent might be the Hofner Club 40 which was played by both McCartney and Lennon. There were a few famous players of the M-75 Aristocrat--Johnny Lee Hooker, Keith Richards, and John Mayer are a few.
M-75s weren't that pricey for many years, when compared to other vintage American guitars. I think the fact that several modern players discovered them (John Mayer, Annie Clark, Brendan Benson) brought them to the surface, and dealers seem to try to hike up prices any chance they get. They're far less common than old Les Pauls and Fenders, and they are quite unique guitars.
I'm sure there are others here who have better insight into this. I just wish that I owned one!