it holds a pretty good amount in addition to the saddlebags:
http://www.mandmcycles.com/default.a...Fcad4AodckMAQg
What I like is that it will mount on the stock F6B Deluxe rear rack, as well as the passenger seat. On the rack, the secret is to secure the forward straps to the passenger handrail. That holds it forward enough to keep it on the rack without laying on the bike's finish. When mounted on the stock seat, it compliments the step nicely to form a rider backrest.
Since I only have to pack for one for extended trips, this and the saddlebags should be more than enough space for me. I've learned to pack pretty lightly. Occupational hazard, I suppose.