As an alternative to any bag, I would suggest the Apex Occam strap. The number of items in your kit would be pushing the limits of this attachment method, but it could work. You would probably want to roll up all the smaller items in your tube and then attach this bundle to your seat rails with the strap. It's a very simple, lightweight solution and can be quite secure. I have one and sometimes use it to carry a raincoat somewhere on my bike frame. Mountain bikers use them for all sorts of things, including repair essentials, such as what you're carrying.