I have a small rollaboard, which does not indicate that it is heavy like a backpack over your shoulder, plus a couple of taxfree shopping plastic bags which hold my film. Secruity and airline personnel do not object to a taxfree bag or two.
My 4x5 or 6x9 stays in the Phototrekker which goes in a sturdy Northface duffle along with clothing. The 8x10 monorail stays in the Supertrekker which goes into a hard-shell blue plastic Samsonite along with the Gitzo 1548 tripod.
In general, I think that you Americans' love story with carryons is coming to an end - might as well accept it and get suitable bags for checked luggage.