I keep Pedialyte in our house at all times. The bottle I have right here in front of me has no listing of any artificial sweetners. It is used in exteme cases only. (I tend to have eagle-eyes when it comes to reading labels, and will not allow any artificial sweetners pass through my front door!
Dehydration, to me, is not taking lightly by any means. It can & does happen with bouts of diarrhea, vomiting & fever. When I was pregnant with my twins, I suffered tremendously from dehyrdration to the point where I had to be hospitalized a few times and be re-hydrated by IV.
Babies can get dehydrated very fast. I learned when ds was just 8 weeks old and in the hospital with pylorec stenosis, a great way to test for dehydration on babies under the age of 1 is to feel their soft spot. If the soft spot is sunken, they are dehydrated. They would not operate until it was no longer sunken. (They will not perform surgery on a baby who is dehydrated.)
If you are not comfortable with Pedialyte, you could contact an herbal path or natural food store and ask if they have a product called "Naturolite" (don't quote me on the spelling of that one!)