I got an idea.

This may sound stupid but, why don't we make a list of devices that work best with portable apps. Devices listed would be benchmarked on different systems (ones with different USB versions, tested on both Windows and Linux (or other Unix-based OSes) with Wine or other Wine-based thing (like CrossOver Linux) and Mac OSX with CrossOver Mac (CrossOver Mac is a version of Wine for Macs) and so on) and then the apps will be used on the devices on the variety of different systems.