I have the smallest Timbuk2 laptop messenger bag that fits my laptop, and it feels great when it's stuffed full of stuff. A change of clothes, a pair of shoes, camera gear, no problem. However, 90% of my trips are just me and my laptop and maybe a book or notebook, and it doesn't feel right with a dense solid object floating inside this roomy bag designed to hold an assortment of random items. The load feels alarmingly disconnected from the straps, and if you carry it by the top handle, it sags in a very sad-sackish manner.

So what's a sleeker and more secure way to carry a laptop and one or two additional flat items? Are there briefcases that can be worn messenger-style on a bike? I'm resisting a rack, since I have a single bike that serves as my commuter and my road/exercise bike, and my commute and other non-workout trips are under three miles.