~30L or 37L preferred; I don't need anything bigger than that.

I like the looks of the Dolomiti but what is most important is the backrest feature as I ride two up w/ my partner and she feels safer with a top case that functions as backrest.

I've got the Givi K100 rack already, which was good luck. (Off eBay, I honestly don't think it's ever been mounted!) 

Condition doesn't matter too much so long as it is functional and still watertight. My K100 is not a looker -- 113k!

Thanks!