The Maclaren umbrella strollers are good for up to 55 lbs. I have one and love it. Not sure how much you want to spend though. If you do a search on the boards, you will find many praises for maclarens.
If you only need it for the trip, you could consider renting also. Although, the price can add up for that too.
Peg Perego probably makes a stroller for larger kids also, but I'm not all that familiar with pegs. HTH!