I have one of these for a sissy bar bag
http://motorcycle-luggage.com/Merchant2/...Product_Count=0
It can ride on the pillion perch or a luggage rack. It rolls on wheels when you want it to. It has a center divider that takes a little getting used to. I may end up taking the sawsall to the center divider to get my laptop in a little easier. (Gotta have my geek box wit me)
Here is a good price on one if you're interested -
http://item.express.ebay.com/Vehicle-Par...cmdZExpressItem
If I need a little more carriage, I lash one of these $20 snow board boot bags onto the back of the Kuryakyn
http://images.marketworks.com/fullView.a...1-1541231dt.jpg
I bought it off ebay, but it looks like fogdog sells them too
