As an active blogger myself one issue I see, aside from getting bloggers to agree to this and finding a price they would accept (very few bloggers will do it for free, unless this publication becomes popular), is the fact that many blog posts simply aren't of publishable quality. If someone told me they wanted to pick a random article of mine and publish it, I would definitely want to edit it first. Web content doesn't entirely work well as print unless tweaked.

The other issue is.. will people used to reading blogs actually read print material of the same type of content? The nature of some of the content might make it outdated and so on