Here's a few skinny guys I found on Google.

[hider=Dude #1][img=http://farm7.static.flickr.com/6198/6145099634_d924715af1_m.jpg][/hider]
^--He has a narrow face/jawline that could indicate a slimmer frame

[hider=Dude #2][img=http://i.dailymail.co.uk/i/pix/2014/01/14/article-2539160-1AA7561300000578-921_634x904.jpg][/hider]
^--The suit makes him appear broader, but if you look a little closer you can see that it's just the padded shoulders

EDIT: The last one won't show up.. :/