Originally Posted by
FBinNY
No, but it wouldn't be hard to make with a bit of standard hardware. You'll need a long stiff flat bar of some kind to take the hooks and spread the load. Then assemble it with the brace inside and hooks outside and bolted through. When hanging it on the bike, use a bungee or strap to hold it down so it can't bump upward and disengage.
The beauty of the DIY approach is that you can orient the computer to ensure good heel clearance. The natural give of the carrying case would take up most of the harder jolts.
I've considered DIY but I'd use a rigid back with the hooks and fasteners because I don't think the fabric will hold up to that for long. And some other design factors, it's back burner.