The soap thing was a joke. It's something that shouldn't really be canon, and kinda is and kinda isn't, but is a darker stain on SW's history. In any case, stygium is great, cool stuff, but does require very specific types of dev threads in order to acquire as you've noticed. And as you've stated you're likely not going to get any stealth tech through without a dev thread. However, you could do a dev thread that's not adhering to their specific styguim and instead use another form of stealth. For example make yourself a Mimetic Suit that doesn't cloak you, but instead changes you to blend into your surroundings like a chameleon. I can't really give you help right now in threadin it as I'm kinda swamped(I think I have like 8 dev threads going on myself), but if you get somebody with you do a good quality thread and provide logical reasoning for you obtaining or building the suit then it should pass, unless you've got other stuff that needs sorting out. Hope that helps man, good luck threading.
From the sound of it what he really wants is something like a "predator" cloak although to be honest something like the "naruni camo variable armor" concept might work, its just the "poor mans version" Its basically armor with a surface that uses tons of tiny sensors, and adaptive "pigment changes" and such to make the "front of the armor look like the background behind it" (from all directions)
or "bend light around the "stealthed" object or similar.
needless to say there is a reason that people don't like it in a pvp environment, and technologically it ought to be a major pain to get to work.