I think someone had made a Pep file for the Covenant Carbine at one point... can't be 100% sure, though; I'd have to look around to see if I can find it to confirm that. As for the other weapons you'd mentioned, I myself have never seen any Pep files done up for those (they've typically been built completely from scratch). Same goes for the Brute costume...
someone on the site a guy had a assult rifle...... i know its not what your looking for buy still
its there sorry i cant give a link to the wep but il try tomorow when im not tired..... its 8 and
i hat late last night too so il try and find it if you want?
sorry i cant help with brute wepons il have a nozy around and il se what i can find ok?