stout

I don't, but I get the strong sense that 991.2 Carrera 7MTs are exceedingly rare—quite possibly rarer than GT3s, GT3 RSs, etc. Of course, that doesn't make them more desirable (see Turbo Targa Slantnose). The only other 991.2 Carrera 7MT a regional rep for the Bay Area could put his hands on recently was a Night Blue car leased by someone at a local dealership. No 7MTs in stock, and none in for service. And this is in Northern California.

As to your guesstimate, that's a tough one. The Carrera and Carrera S are the bread-and-butter 911s. They carry the line as and until the other models are added in, and I suspect they continue to sell fairly well to customers who "just want a 911" after the Targas, GTSs, etc are available. And then…how many 991.2 Carrera 7MT buyers get talked into ordering an S, or a Cabriolet? The take rate for the manual may be higher than you think, given the take rate for the 6MT on the new GT3, but the Carrera coupe 7MT has to be a pretty rare bird. My guess is a decent percentage of North American 991.2 Carrera 7MTs are represented here on Rennlist—I can think of several on this forum, but it might be fun to count them up by starting a thread/registry for these 911 "non events."