Tang, I was in a similar situation earlier this year. I have a Custom, I do not want a sissy bar, I need a passanger seat once in a while and I wanted a decent-size luggage. I did a lot of research and poking around.
Finally, I found a near-perfect solution in the following combination:
- Custom World Intl. luggage rack (I got the oversized model, although I would have been with the regular too, I am sure. Anyway, it's like a $25 difference or so...) it's the rack only, although you always have the option to add a sissy bar later.
- Bestem hardbag - It mounts on the rack with a mounting plate, everything fits very well and it is trivial to install and mount. It is a big size, 50+ liters or something like that, it fits 2 large helmets comfortably. It is lockable, it has a light (can be either running or brake), it is like a Givi knock-off, I was told, cheap but indeed inexpensive, and it works perfectly).
I got both on eBay. The installation increased the utility of the bike many-many times over. I can fit a relatively large pile of groceries in it. (OK, not a 24-pack of Bounty rolls, that's for sure...)
The hard bag has a handle and it can be detached in a few seconds. One of the best additions I could have made. IMO.
'07 Vulcan 900 Custom, Candy Fire Red
'05 Suzuki DR-Z 400s