Dean7, The Timbuk2 bags have a laptop compartment that is attached to the inside of the bag via a 1.5" strip of fabric on either end whose function is to allow the inner compartment to float inside the bag. If you grab the strap on each end where it attaches to the bag and pull the ends apart until the bag is stretched tight, the laptop compartment is still free to float around a little bit. It's a great design if you want to pack a lot of oddly shaped things inside the bag (which is the purpose of a messenger bag, after all) but bad for someone like me who doesn't carry much stuff.

The Vario rack is exactly what I need. I could strap my briefcase to it, or a small bag of groceries or whatever else I want to carry. It says it can carry eleven pounds, which is plenty for 99% of my trips. I'll have to check whether it will work with my seat post, though.

Cyclaholic, you have me thinking that I ought to hack my Timbuk2 bag or sew my own custom solution to this problem from scratch, but in a few seconds my natural laziness will kick in and I'll forget all about it