Carrying a laptop on a motorcycle is not as simple as you might think; even if the bike in question has hard bags attached, many times they are not shaped properly for that application. Dowco's Commuter Briefcase is made from rugged black nylon and looks like a standard briefcase.
At 16" long, 4.5" thick, and 12" wide, it holds a laptop and charger, and includes the usual compartments. The D-rings at each corner (with detachable straps) and two long Velcro-backed straps on the back of the bag create an impressive mounting system.
I have found that almost no matter what type of motorcycle I am riding, there will be a way to safely and securely attach this bag.