Does anyone do this? I have a few bikes and don't want to put racks on all of them. I primarily commute on two of them, but occasionally ride one of the others. With the weather warming up and no showers at my office, I need to get my gear off my back so I don't sweat so much. I was thinking it would be nice to get something I can just drop my bag into so that I don't have to move everything into my mess bag on days I ride a bike without a rack. Also, how annoying is it to have all your junk on one side of the bike? If I have a heavy laptop on one side, is it going to drive me crazy? Should I just find a good way to strap my bag to the top of the rack?

Not to be a weenie, but I don't want to use a basket. Panniers are bad enough.