I have a top tube bag, too, but when I put lots of stuff in it it leans to the side so my knee hits it when I pedal. So it's of limited use.

I also have a handlebar bag, but I prefer to use it only in cooler temps to hold outerwear that I may want to put on or take off during the ride. It tends to hit the adjuster thingies on my cables which leads to shifting problems, plus there's too much other stuff that needs to attach to the handlebars.

Really, if Bontrager hadn't cheaped out and changed the design of the large bag, it would be a near-perfect solution. I would happily pay a higher price to get a new version of the bag I'm replacing, but I refuse to pay what they're charging now for such an inconvenient product.

BTW I've also checked Louis Garneau, Lezyne, Timbuk-2, and whatever else is sold by REI, Colorado Cyclist and Performance. And Rivendell and Brooks.

If I can't find anything else, I'll go with the largest "medium" bag I can find, which might be the Topeak. I need to double-check the Banjo Brothers site again to see how big their medium bag is.

Also, fwiw I think Lezyne's "large" bag is a really smart design, because it has two separate compartments. Unfortunately it's only 58 cubic inches total.

http://www.lezyne.com/en/l-caddy