For the OP's stated needs (exept for the backpack aspect), I'd strongly recommend the B&R U-21NX expandable uprght, together with the B&R BB104X expandable computer case.

The upright, in its normal configuration, meets airline sizing standards. When you need more space and will be checking the bag, a built-in expansion (enabled by an integrated zipper) will give you extra room.

The computer bag also expands, in the same fashion - it gives you extra room for either additional computer gear, reading material or even an exra shirt or two in this bag that will bring into the aircraft cabin with you.

With this combination, US to Europe trips of 7-10 days are very do-able.