Just finished organizing regular tagged feeds and was wondering - is there a feeds for unanswered questions in specified tags?
Somehow didn't find them. :/
There certainly is! I have written a small application that does this. It's called stack2rss and it works by converting API request results into RSS feeds.
The general format for a feed that does what you describe is:
An example that displays unanswered questions tagged
'windows' on SuperUser: