I spied it a few days ago in the incredible Fab Gabs vintage shop. If you haven't happened upon their beautiful collection yet, you will probably get all kid-in-a-candy-store about all the dresses, slips, coats and things. The photos are really good at conveying fit, form and details, the listings are generous with information about the garments, and the whole shebang seems like one very classy operation.
Now, this candy-striped dream needs to appear on my doorstep!
* Edited: I just saw this dress in their shop - gasp!
Too much goodness in one place.*