Request HN: folding comments

It would be great to have a firefox/chrome extension (ff preferred for me because chrome is too insecure without noscript et al, but whatever's easiest), or better, a javascript bookmarklet, to implement a "collapse/expand" feature for HN comment threads.

I took a quick look at the source, and everything's in non-nested tables, so it's a little more work than "hide everything under this div because it corresponds to the replies to this thread," but it shouldn't be too hard.

I'd do this but I'm swamped with work and don't expect to have free time for months. Don't know how many other people would appreciate this feature, but I thought I'd put it out there in case someone likes it and has the time to get it done before me.