The Star Tribune has started doing something very similar. Their bigger, more in-depth pieces are only available in the print edition, which I think is an awesome idea, partly for a selfish reason. When they were available online for free, I'd often ruin my Sunday ritual of reading the paper while watching a ballgame by spending an hour or so on the Web site (just couldn't wait for those investigative, special stories).
Funny thing, too: The past few weeks, it's been much more difficult to find the Star Tribune on racks in convenience stores. I mean I've had to hit three or four different stores. Perhaps it's just my imagination, but I don't think so. I think folks are completely OK with paying a little money for such high-quality work. Realistically, why should a 100-plus-inch story that took six months to investigate (and thousands of dollars in employee hours) be given away for free?