The GIVI mounting frame is something worth discussing, too. It's built to take abuse and to support substantial weight. The frames are designed to accept any of the GIVI MONOKEY cases, which means anything from 21 liters to 52 liters could be mounted to the same frames. In a 45-55mph crash that totally destroyed one side case, put deep gouges in my crashbars, and busted me up extensively, the GIVI mounting frame suffered not one bit of damage. I'm not sure I can overstate how well this frame is designed and built.
In 2007, I had wrestled with side cases and touring luggage for my Suzuki V-Strom DL650 until settling on the GIVI E21 cases. The E21 cases are 16" x 14" x 5”, top-opening, and have a 21 liter capacity. Not small, but not huge enough to radically change the lane-splitting clearance of the V-Strom. Another advantage of the GIVI cases is the MONOKEY™ locking and mounting system that is custom designed for specific motorcycles and adaptable to every MONOKEY™ case GIVI makes. You could have E21 cases for commuting and E44 cases for touring, if you have the cash. All you would have to do to change luggage is use one key to unlock and remove the little cases and the another key to install the big guys. You can buy the E21 cases in flat black or get the top portion of the case painted or supplied in cruiser chrome'ish.
In theory, all of this makes the E21 cases seem pretty practical. In practice, the small top-loading cases are difficult to make useful for more than around-town errands and minimal gear storage duties. For a recent 10,000 mile trip, I ended up dedicating one case solely to camera and computer duty and the other to carrying a Darien jacket liner, a bike cover, chain oil, and a few bits of maintenance equipment. Both cases were stuffed to capacity with that light load. This restriction put serious demands on my tail bag load and resulted in a top-heavy, wind-sensitive load that turned dangerous on the Dempster Highway.
Even earlier in the trip, contact with another rider's soft bag (caused by a sequence of events that neither of us is proud to describe) at about 15mph caused my right side GIVI case to disintegrate like a plastic Easter egg while doing next-to-no-damage to the soft bag. Some creative use of Gorilla Glue and a mile of duct tape put the case back together where it lived until I decided to crash on Canada's Dempster Highway and even the duct tape failed to hold up for that incident.
In all, I still like the E21 cases for commuting, although I hardly ever have much in them on a normal day. For touring, unless all you're packing is a toothbrush, one change of underwear and socks, and a spare tee-shirt, I think the E21's are too small and too fragile for that duty. Trust me, I tried and failed in the attempt to prove that statement wrong.