To rank academic papers you'd need a way to establish certain people as authorities within each field or area, and make their vote stronger. This authority ranking would surely have expert input initially, but I would expect that Citeseer and Google Scholar may be good places to look for inspiration on ways to crowdsource authority rankings.
For starters look at the Page Rank paper (named after Larry Page, not web page). Academic papers need something richer than page rank, but since tens of billion of web pages can be ranked for arbitrary queries, the volume of academic papers should be fime.
Ranking algorithms are one of my favorite subjects, and they are as challenging as they are important. "Search" has little to do with actual searching, it's really a ranking problem. Google's search was the first good ranking scheme for internet search, and their "I feel lucky" button was a way to show that off.
Happy to discuss by email.