A reader sends along a list of the law schools from which Yale has recruited most of its current faculty; I haven't checked this for accuracy, though it looks right. Some Yale faculty left and came back, hence are listed with more than one school.
6 from Stanford University (Ayers, Donahue, Ellickson, Gordon, Romano, Whitman)
6 from University of Chicago (Brilmayer, Fiss, Kahan, Kronman, Langbein, Meares)
4 from Columbia University (Ackerman, Alstott, Merrill, Rose-Ackerman)
3 from University of Pennsylvania (Ackerman, Damaska, Hansmann)
3 from University of Southern California (Graetz, Resnik, Schwartz)
2 from Cornell University (Kysar, Macey)
2 from Harvard University (Gerken, Jolls)
2 from New York University (Brilmayer, Hansmann)
2 from Northwestern University (Brooks, Smith)
2 from University of California, Berkeley (Post, Siegel)
2 from University of Michigan (Burt, Shapiro)
1 each from Duke University (Chua), Georgetown University (Eskridge), Oxford University (Sweet), University of Arizona (Coleman), University of California, Los Angeles (Priest), University of Texas (Balkin), University of Virginia (Mashaw), and University of Wisconsin (Schultz).
If anyone cares to compile similar starts for Harvard (which has done less lateral, and more junior, hiring than Yale however), please feel free to send it along.