Well, if we're talking about unexpected neck elongation, there's this Deviant ART by Silverbolt2012:
http://silverbolt2012.deviantart.com...-neck-63580530
There's also neck stretching featured in Animewave and Kecomaster's Deviant ART accounts, but that's mostly part of images featuring full-body elasticity powers.
There's also the Reno's Rubber Room groups over at Yahoo, but it's mostly full-body superheroine-style stretching too (although, if you search our RRR & RRRRed message archives for 'rokurokubi', you'll find tons of webfinds!).
http://groups.yahoo.com/group/renosrubberroom/
http://groups.yahoo.com/group/renosrubberroomred/