I'm having the same dilemma. DS has autism and tires easily, but he is 70-80 lbs. I thought about buying a special needs stroller, they look like the umbrella strollers, but can handle more weight. The problem - they cost over $1,000. I found a company that rents them for $50 a week, but I'm scare something might happen to it. I found a double umbrella stroller by Joovy. It's called the Groovy 2 and it holds more weight than the normal Maclaren strollers. I called the company this morning and they said the maximum weight is 55 lbs, but it could handle more unofficially. It is costly, about $280 and I think it might be worth the investment since we are newly purchased AP holders and we frequent alot of venues in downtown Atlanta.
****I posted this response on another thread, I thought it pertained to this thread too, so I reposted on this one.****