I've thought about them before, but they wouldn't have worked at the time (my backpack was too large to fit in one). However, now that I've decided to split the load as it were, I'll revisit the idea.

I was going to ask how flush with the top of the rack it could mount; I saw customer images where one had a Igloo cooler on their rack. That is good, as I really want to run with a trunk bag...