I've seen screenshots of them on the main site, and I've seen characters who had them flying around. How does one get them? The invention system? Mission reward?
invention system. you can see most of the recipes for sale in Wentworth's or the Black Market Truck.
they're pricey though, millions of inf
They're an Uncommon Pool A recipe obtained by killing stuff. Your best odds of getting them are between 10 and 14, because there are only ten or so other uncommon sets available at that range, so relatively you're much more likely to get an invention that at later levels where there might be several dozen sets available at a time.