I've used Loctite 330, I think it was that anyway, it was blue! on my Impreza gearbox. On the layshaft to hold the 5th gear locknut. Once it sets though, you'll have big trouble getting it back off again!!
As for metals, where I work it tends to different thicknesses of Alclad(aluminium alloy clad with duralum I think) or titanium. Never really seen stainless steel kicking about or many parts manufactured from it.
Hope that helps.