Interesting thought... Right now I like Sandy's approach which is application volume. Here's how that would look using BusinessWeek numbers.
1 Harvard Business School 9524
2 Stanford GSB 7204
3 Penn Wharton 6819
4 Columbia Business School 6666
5 Northwestern Kellogg 5270
6 MIT Sloan 4782
7 NYU Stern 4501
8 Chicago Booth 4299
9 Berkeley Haas 3627
10 Duke Fuqua 3506
11 Yale SOM 2963
12 Michigan Ross 2722
13 Dartmouth Tuck 2528
14 Virginia Darden 2515
15 UCLA Anderson 2458
16 Texas McCombs 2259
17 Cornell Johnson 2001
18 USC Marshall 1983
19 UNC Kenan-Flagler 1764
20 Georgetown McDonough 1630
21 Carnegie Mellon Tepper 1540
22 Washington St Louis Olin 1529
23 Boston 1387
24 Indiana Kelley 1217
25 Notre Dame Mendoza 1086
26 Emory Goizueta 1037
27 Maryland Smith 992
28 Vanderbilt Owen 894
29 Rochester Simon 851
30 Ohio State Fisher 789
31 Washington Foster 772
32 Purdue Krannert 771
33 Boston College Carroll 719
34 Michigan State Broad 602
35 SMU Cox 565
36 Rice Jones 544
37 Texas A&M Mays 537
38 BYU Marriott 476
39 Minnesota Carlson 452
40 Georgia Tech 445