I have a Peli case and I just love it...one of the best investments I ever made for
camera gear protection...when said gear is within my immediate control and possession...
I would NEVER though use it for air travel...it may be water resistant, it may be dust resistant, it may offer first rate impact resistance, it may have a "you break it we replace it" warranty...
But I refuse to put my gear into "checked baggage"...and by "gear" I am referring to body and lenses...
Those items go in a soft bag which meets the carry on requirements for size...and the Peli stays at home.
I guess there would be nothing wrong with checking in your empty or nearly empty Pelican case/s with an ATA approved lock on it...and maybe some less valuable accessories in the case/s...
As mentioned however these cases SCREAM-STEAL ME!!!
For my purposes, the case is a mobile "vault" of sorts that offers impact/water/safe storage benefits...and it sees all travel EXCEPT AIR...and then I make it a habit to keep it out of sight as much as possible, and always within my immediate possession and control.
If you intend to put your 5-6 lenses and DSLR and accys. into one case you WILL need a BIG one with wheels...or two smaller ones...I find that one DSLR body and three lenses are about the limit for the Pelican 1550 model (one body, a 24-70 f2.8L, a 70-200 f4.0L, a 50 1.2L and a spare battery and charger and a couple other very small items). That arrangement gives comfortable room between items without overcrowding. Your experience may vary...
Whatever you end up with...I would suggest that you take your gear with you when you shop so you can trial fit the gear you have and make sure it's going to work out for you.
When I internet searched for the Pelican, I thought for sure I would end up with a 1400 series case...but when I actually took my gear and placed it onto the foam I quickly realized I was going to have to go bigger to allow the distance I wanted between lenses etc. AND to get the depth (top to bottom) I wanted for the DSLR body...and ended up with the 1550...
I wouldn't know what size to suggest if you are going to get one case except to say it's gonna be BIG for what you described...
I will hazard a guess that a pair of 1550's would hold your 5-6 lenses and one body with some accys...you might be able to "double" the 1550's exterior dimensions to get an idea of the size of a single case...
HTH
Cliff