I'm wondering if the OP meant this is literally double casting, as in during a show's run you have two people alternating in the same role, or dual role as in, one person plays more than one role.
As a crap ton of shows utilize dual role, I'll list the ones that pop into my head, as there's quite a lot.
Spamalot
Children of Eden (it's not required really, but it's the way it was conceived, same with Spamalot...sort of)
Mary Poppins does this for a few roles doesn't it?
Once
Again, quite a lot, and I know I'm missing some.
Now double as in alternating.
POTO in London does this or at least I know it did for a while, as in the Christines each had 4 shows a week. I think it was the same for the Phantom at the time too. Of course here, is a 6 to 2 ratio. Same with Evita...I think? That role is WAY harder than Christine, I can't imagine even doing it 6 times a week.
Yep Wicked did it for a while overseas somewhere, which I wish they'd do here, the standby goes on a lot it seems in NYC and the tour. That role is just under Evita in terms of being a beat for the Elphabas.
As for the now open Frozen in DL...um..guys it runs every day of the week, of course it's gonna have multiple casts. That's a given just in terms of labor laws. If Disney legally could hire one cast to do all shows a day, every day they probably would sadly. People are already saying they hope there's multiple people doing these roles...well DUH! It's illegal just in labor laws and AVGA bylaws. I believe there are four casts, and the two lead ladies are double cast, so that would be 8 Annas and 8 Elsas, if they even stuck to double casting, I don't know if they actually did, but when I was told that, the definition of double cast could have just meant something different.
Granted double casting is a casting choice rather than a necessary or artistic vision like dual role. Spamalot uses dual role to keep the Python conception that every member played multiple roles in the film it based on, plus all their films really.
Children of Eden uses it to reinforce the patterns we as humans go through until someone is brave enough to break it.
Double casting is used for ease on the performers so they don't "die" during the run of a demanding show.