I've used a BeagleBone Black to create a USB gadget in the past. I'm currently contemplating a project that would want to create several gadgets controlled by a single PC, though, and I've not been able to find a board that allows that.
Does such a thing exist--either as a singleboard product like the BeagleBone or as an add-on card like a PCI card? Has anybody heard of someone attempting to do something like this with off-the-shelf hardware? Simple googling has not been effective.