What you need is an either:
A news aggregator which archives everything. Newsgator is an excellent example although there are (I believe) others.
http://www.newsgator.com
A web based news aggregator which does the same thing (archives). Most server side aggregators are better at this than client side aggregators.
http://www.bloglines.com/
A rss to email aggregator so that your rss feeds arrive in your inbox and are archived there.
I honestly don't think the solution is another standard that replicates what we have. What you're looking for is just the right tool.
Scott