When my children were small, they didn't require anything more than we did, because they didnt' expect it. We took them at 3 1/2 and 6 the first time and didnt' take anything more than a fanny pack for our tickets and cash. Once my 2 boys were potty trained (at 28 months) we never required more than a fanny pack and even before that, a small backpack would do. We were on a tight budget, but we didnt' carry food or water in. What could you possibly need a rolling back pack for? It's like luggage. To me a vacation is about ease. That's the joy of potty trained children. You don't need to carry anything for them. Even diapers fit in a regular backpack if you need a few. An inhaler fits in a fanny pack too or a regular backpack at the worst. And if you need oxygen due to emphysema, sorry, but it's hard to have sympathy for self-imposed health problems like that.
My DH and I are going in Nov and at this point I wonder how my 2 DS ever survived childhood without "car" strollers, portable dvd players, me waiting on them hand and foot, etc but guess what, they did and very well. They're both in college and doing VERY well. I have raised two independent adults now and they just shake their heads at parents who feel the need to fulfill every whim. No child ever starved by missing a snack or learning to wait.
Handicapped people, through no fault of their own should be able to bring whatever they need, but everyone else should just deal. Those of us who follow the rules and expect others to are just out of luck I guess.