I checked into this thoroughly before our trip a couple of months ago. There is a company called Chamilia (chamilia.com) that has a special line of disney charms. They are absolutely stunning and quite a large variety, I would say around 30 beads. You can view all of the charms on their website. They are compatible with pandora, but not sure about trollbeads. My friend has a trollbeads bracelet and she said some pandora beads will not fit.
Prior to our trip I posted here with the same question as you, but didn't get a response, as I assume this is rather obscure. I contacted Chamilia directly and they told me they were available in WDW, but couldn't tell me where or what the selection would be like. Upon arrival in WDW, I inquired and found out that they are available in 3 locations. First location in at the jewelry counter inside of World of Disney in Downtown Disney. Second location is in the jewelry store on Main Street in Magic Kingdom (the right hand side of Main Street facing the castle). The third location was in the jewelry section of the big
Disney store on the left of Main Street. The DTD location had the biggest selection by far. In MK, the selection was quite limited and they said they get shipments weekly. In the end I didn't buy them, as they didn't have the ones I wanted, but they are really beautiful.
I noticed a jewelry store on the main street (although it's not called main street) in Hollywood Studios. I wondered if there might be some there too, but I couldn't go as my kids were melting down and my DH shot me a look like, "you're kidding right."
Apparently the customer service counter within World of Disney at DTD can tell you the location of any product in WDW, provided you have an adequate description. You could ask there too.
I hope you have good luck and a great trip!
P.S. Thank you for the stroller post yesterday!! My grandfather was from Scotland, and I hope to visit someday.
