I use an expandable "T-Bag". Folds down when not in use, has an attached rain cover and holds a ton of stuff in all the nooks and crannies. These are some good sites that have a decent representation of whats available for various styles. I use mine more than I thought I would originally. Good luck.

BobW.

http://www.revpack.com/motorcycle/products/TourPack.html

http://www.nelsonrigg.com/riggpaks.htm

http://www.tbags.com/productsall.aspx

It's all good, but it's all make believe