They actually had these...
They were an off the shelf, could buy in any WalMart, soap dispenser. The problem with them is the leaked like a sieve. Having owned one myself, it was not uncommon for me to fill up all three containers only to find $20 worth of shampoo, conditioner and body wash on the shower floor the next evening. I can only imagine how much soap Disney went through with an entire resort filled with these things.
At least the new dispensers seem to be ones that just hold a pump bottle which should greatly reduce if not eliminate the leaking problem.