I think I read that the beginning of "Territorial Pissings" is like that, too. It's Krist singing into Kurt's pickups.

As for cool noises.....

A couple years ago I wanted to practice working with feedback without disturbing my family with loud noises, so I busted a cheapo pair of headphones in half and glued the two speakers side by side. I then plugged them into the headphone jack of my amp and just experimented with different proximities and angles to the pickups. I got some of the coolest noises I've ever heard out of those things. Unfortunately, it didn't help me very much in terms of mastering feedback, because the noises were so different from regular feedback.

I wish I still had that headphone thing; it stopped working after a couple days. I think the glue ate away at the wires or something.