The airlines I have traveled witrh allow 1 carry-on, and 1 briefcase.
I carry my underwater video camera setup in a pelican case. That, they consider my briefcase.
For all my other treasures, I use a standard (and cheap) 21" carry-on suitcase, with the rolling wheels. I took the handle mechanism out of it, because the handle mechanism takes up a lot of room inside the case.
In a 21" carry-on you can put a lot of stuff. I wrap some of my goodies in plastic grocery bags or ziplock bags for some cushioning. I don't wrap it too well, because the security guards always unwrap everything.
Also, I always get picked as the random security check, so no need to wrap things too well.
Anyway, I try to keep things simple. I have found that compartments take up too much space in carry-ons. I always take so much stuff that I need to cram as much as I can into a small space.
I also go to Office Depot, and get fragile stickers to put on my goodies. They are bright flouresent orange. They help me spot my stuff, if it should happen to "walk away" by themselves. I recommend making you your bags really ugly, and really bright. Something easy to see in a crowd. Something a thief might not want to carry.
I sometimes lock my carry-on and pelican case after all security checks with those lock ties, although this can be a hassle if you need to get into your stuff, because they need to be cut off to open your case up.
My checked bag is a locking suitcase. In it I have a bicycle lock and cable. When I leave my hotel room, I put some treasures in the suitcase, lock it up, and cable it securely to something. It won't stop a determined thief, but it will slow them down, and discourage them a little.
I also carry liitle Christmas bells that I put on my hotel doors, so it jingles when it is being opened. I don't like surprise visitors. After being robbed once, I have learned.
Good luck.
