Ok this is an old thrread but I just found it.
If your not worried bout looks but want HUGE capasity and back rest for little money........Use the trusty "sea bag" from an army navy store, or ask a Vet to get you one on base. Usually around 30- 40 bucks, I cant remember as mine was issued to me. Fill it, put a travel pillow in it right at the middle, strap long ways across bike or upright if you have a old school sissy bar. Works like a champ and you got everything you need and then some.
