Tabbloid is a long-overdue service that takes your RSS feeds and converts them into a neatly laid out pdf files that are emailed back to you at a desired frequency. It's not perfect, but it's the best I've seen so far and there's an API. By Hewlett-Packard, a company that once branded Print buttons and makes blogs printer-friendly. Next, they need to team up with Adobe and insert some pdf ads.
Update (Dec 10): To respond to Max's thought that "converting RSS into PDF won't sell any more ink" in the comments section: if this thing takes off and people start printing their RSS feeds, HP with its 45% share of ink market will be the first to benefit. It's pretty much like the Michelin guide the company created to get people to drive more and replace tires sooner.
-- Your personalized printed newspaper (Oct 2005)
-- Dutch blog content to be turned into newspaper (Jan 2006)
-- Guardian: Print Your Own Newspaper (June 2006)