I got myself one of these
Inside I have:
5d2
1d3
Rokinon 14mm
35L
50L
85L
45 TS-E
135L
70-200 2.8L IS
Filters, blower, memory cards, batteries, etc etc.
Oh... and it fits my 15" MBP and meets carry on standards.
I also have a flipside 400aw that I use when I need to pack light. I can't use shoulder bags.. they kill my back