Thanks to everyone for the suggestions! I FOUND ONE! Hooray... and it was right under my nose.
I found it online under their petites. They were sold out of all the sizes in the regular sizing, so that's why I couldn't find it - didn't even show up in search results.
Well, unfortunately, it was only available in a Large in petites...boo. So today I went by the local Gap and they had them in stock in the regular sizes! So I tried on the Small and it fits perfect and the fabric is really soft... I'm so excited.
Best part of this shirt... it's less than $25!!
P.S. The reason I wanted the shirt so badly is because I've pinned several outfits that have a black and white stripe top like this that I really want to duplicate...and now I can. :)