Workaround found!

Hadn't yet seen a reply to the bugzilla comment, so I kept fiddling with the feed in yahoo pipes. I finally discovered that if I take all their category feeds, combine them, and sort and filter them, then the result is a feed identical to their main feed, yet DOESN'T crash the 770 reader.

So, here it is for all to enjoy:
http://pipes.yahoo.com/pipes/pipe.ru...6g&_render=rss

Is there anywhere else I oughta post this so that everyone knows about it?