I've seen the tapestries up close, they are awesome. Wish I'd bought a set when I had the chance to get them at their original prices.
And as for the real paintings in the stretch rooms, they get repainted about once every 2 years, from a master key which makes them virtually identical. Every once in a while an artist assigned to re-paint them will sneak in a little personal touch, but they are scrutinized pretty heavily before they get put up in the attraction, so those with modifications rarely see the light of day (or dark of the chamber, as it were.)
I worked at the WDW mansion for years and the stretching room (it actually stretches as opposed to Disneyland's elevator) is one of the coolest things to see how it actually works. The 'hallway' from load to unload areas leads behind the stretch room and the mechanisms that stretch the room are super close...got my coat caught on one once...very scary.
Next time you're at the Mansion at WDW, make sure you take the chicken's exit just past the stretching room...they have framed versions of the portraits hanging in there where you can see them up close. Also check out the cool details in the hallway used to bring wheelchair parties into the ride, like the service bells and the key board...where the key to the attic is always missing.