One might safely guess that, rather than creating something entirely new, Southwick, heeding the Ivy-covered zeitgeist, simply blew the dust off an old, time-tested design they found amidst a stack of papers on a closet shelf. The name of the model, which cannot be found on the company's website, is the Cambridge. As in England. Or, more likely, that Massachussetts town that sits happily on the Charles. Best I recall, there's an Ivy League school there.
I know less than I'd like. What little information I possess comes by way of rumor, and, if I may be so bold as to ask, I wonder if anyone might contribute more.
One further wonders if Brooks, now the owner of Southwick, would be willing to use the model as a foundation for a new line of made-in-America clothing that, in the spirit of nostalgia, hearkens back to the era that made the "Brooks Brothers Look" famous. Brooks has been Southwick's largest account for decades. Now Brooks could use their factory--their own cut-and-sew operation--to reintroduce the style for which they were once well known.
Time will tell. That a Brooks poplin sack is still made somewhere overseas, even after the purchase of Southwick, makes little sense. If the use Southwick for the Fitzgerald and darted versions of the Madison and little else--well, again, this makes little sense.
At the very least, there is the Cambridge--available to/through your local Southwick retailer. Le Ivy est mort, vive le Ivy, eh?