Would something like
Pedialyte be better? Many brands, plus I am almost certain that this sort of thing can be found powdered. Not supposed to exclusively use electrolyte solutions for re-hydration over long period, but it's just the ticket for starting re-hydration. IMHO, these are far better - especially for infants and kids - than a sports drink.
Edit: Here's an example -
Gookinaid Hydralyte - it's powdered and claims to be even faster than Pedialyte. Caveat Emptor, of course, but this sounds better than GatorAid.
HTH,
Tom