UPDATED 07/13/06 - The Sesame Street line hasn't seen it's first wave yet, but the first exclusive is already out - Super Grover.  Here's two sculpt patterns for Grover, one with the hat, and one completely nekkid.  They are at least 10% bigger than the final product.

Alas, the first series of regular release figures was scheduled to be Guy Smiley, the Two Headed Monster, Ernie and Cookie Monster, but they never saw the light of day.  Here's a 105 of the unreleased Guy:

Each of the figures in the first wave was supposed to come with a letter from the alphabet - here's a test shot of an A and a B.  Obviously, these never made it to production.