I usually use a backpack (smallish) for my laptop, magazine, a few electronic knick-knacks and occassionally an extra shirt/sox/underwear on a day trip, but due to having hurt my left shoulder, I can't wear the backpack with both straps.

As long as I'm only wearing it over my right shoulder only, it seems silly (and ergonomically bad) to have a backpack so I've been looking for a "monopack".

I want one that naturally falls in the middle of the back when the single (hopefully padded) strap is across the chest, and it needs to be large enough to fit a 13 inch laptop.

Bike messenger bags tend to be too flimsy, and many of the nice "ergonomic sling bags" are more "purse" sized.

Can anyone recommend something that would work? Since this is also the bag I take with me when I have a wheeled carry-on I don't want to go to wheeled laptop bag, it's gotta be something I sling over the (good) shoulder.