To date I have used a backpack, Lowepro, and a computer case to carry my cameras on board when flying. I would like to switch to a hard case but I would be back to lugging it around in airports. Some larger cases have wheels but it seem excessive. I see people stuffing and pushing and crushing bags in the overhead so a hard case seems like a good choice. What's a smart choice for a medium format or 4x5 and lenses? I also see that TSA combination locks are available, anyone use them and where?

Curt