I had a quick look for metal and aluminium headsets on the eBays and the Googles and also found bupkis. I think the problem is super high build quality stuff like that is more likely to appear in a dedicated set of headphones if anywhere rather than a combined headset. I suspect you're either going to have to sacrifice the built-in microphone or the metal construction.
If you opt for the latter I can't help but recommend the Logitech G930s I just got. They're pretty plasticy other than the band frame but the construction seems solid enough (they give them a 2 year warranty which is more than most), the sound quality is the best I've had (which probably isn't saying much but I'm impressed by them), the mic is pretty freaking good for a headset, and that shit's got 7.1 surround which is awesome for the games that support it. There's also the G35s if you aren't into wireless but I think it's the bomb (I get about 10 hours on for 2 hours charge).