rss feed for categories with subcategories

Is there a way to display an rss feed for a category and its subcategories? I have an onlinemagazine with about 20 - 30 categories all within my magazine-category that doesn't have any articles itself:
Magazin (0 articles)
--category 1 (20 articles)
--category 2 (0 articles)
----category 2.1 (10 articles)
----category 2.2 (12 articles)
--category 3 (5 articles)
etc...
How can I create an rss-feed over my complete magazine-category (with parameters like the latest 30 articles, only intro text, no html etc...)
Joomlas built in feed component doesn't seem to work here, I cant select a cagegory there. Ninjarss shows empty feeds and Foobla seems quite expensive.
I managed to create a feed output when I appended /index.php?format=feed&type=rss to my sites' url but this gives me the whole articles with images and only as many as there are displayed on my frontpage.
Regards

bump... doesn't anyone have an idea?

Foobla seems to be the only choice, but I've never seen it.
I'm currently working on my third Flexi-site and RSS is missing on all of them yet. Maybe I'll give Foobla a try once I finish this one.
I usually use NinjaRSS.

Would be great to have it very configurable, like the module.

Idea: just render Flexi-module output to a rss component.
I mean, it would be a convenient way to make a module in some pseudo position, or take an existing module, and render it into a rss view.

How about modifying NinjaRSS default view, to optionally render just from Flexi-module positions, instead of ->content; in its view. Would that work?

@horsey,
I bought foobla last week but there are problems.
I'm in contact with their support to straighten this out so you might want to wait a bit before you buy it
I'll report on how obrss works together with flexicontent.

We are using obrss and it is working well on our site, have a look here

www.energymag.be

There are 3 feeds (1 in french, 1 in dutch and a bi-lingual one on a hidden link).

The FC version is still 1.5.4 maybe problems comes from new version of FC.

I have very strange results here where obrss creates very strange urls:
usually FC urls are something like domain.tld/category/category-id-category-slug/item-id-item-slug
but with obrss I get:
domain.tld/editors-name/item-id