The stealth suit is awesome, I agree. Especially for Point Lookout's tough crowd of inbreds and super ghoul reavers. In FNV, there's the "NightKin" Super Mutants, who I think have the ability to go invisible, so maybe there's some way to steal that power and use it for yourself without mods?
Yes, the source of their power are Stealth Boys, aka those things which in Fallout 3 were single use and of a limited duration. In the earlier Fallouts they had a finite number of uses but it was more than just one and lasted a bit longer from memory but again didn't last forever.
