DON'T GO THERE!!! I went once for a simple poster and walked out with $200 in prints. That place is evil!
For something different... There is a shop in HS on the same street that ToT is on. They sell hand drawn sketches. They are one of a kind and super cool. Not cheap but worth it imho. I can't remember specifics as i haven't been to the studios in years. But look in DTD see if they have the sketches and if in the studios check some of the shops on the same street that ToT is on. Sorry this is so vague. Most of WDW sells the same old *stuff* but if you really look carefully in the nooks and crannies you can find some terrific one-off stuff. I have on my wall a hand sketch of Mickey dressed as a Fireman (from around the time of world trade center bombings) and a sketch of Dale in his Rescue Rangers costume.
The DTD store will have the posters you want and much more...