Last year, one of our favorite laptop backpacks (and really, it still is) was the Booq Boa Squeeze. More of a padded gear tube with arm straps and plenty of pockets, it managed to be stylish, compact, sturdy, and roomy all at once.
For something a little bigger--no, make that a lot bigger--Booq's sizable Boa Flow might be what you're looking for. OK, honestly, the bag's gigantic. A large reinforced black-and-orange curved shell-shape lined with some useful pockets and plenty of interior room, the Flow will resemble nothing so much as a giant Koopa shell or neon Teenage Mutant Ninja Turtle costume. It's not light, either: at 4.5 pounds for the medium-size Flow and 4.9 pounds for the XL-size, this bag's heavy even when empty. It also isn't cheap: $199 might be too steep for many bag-buyers. It's twice the price of the Boa Squeeze.
To its credit, however, it keeps its shape and stays strong. A large interior, nearly enough space to be called a weekend suitcase, can hold clothes, small packages, and whatever else you can think of. Laptops actually slide into a separate rear-zippered compartment, which has very thick and rigid padding. Even semithick 17-inch desktop replacements can fit here, no problem, providing you've bought the XL (which, incidentally, happens to be same price as the M).