jw, I am a long time low carber and have never really found a good replacement for pasta. You can try zucchini (the green squash, grated or peeled into "noodles" or "zoodles", so to speak), or the spaghetti squash (all split/pulled up with a fork), but there is really no substitute for pasta.
HOWEVER (!), If you are OK with ingesting large amounts of fiber (I can't do it- potty nightmare), there is a product out there called "Dreamfield's Pasta" that legitimately claims only 5g of digestible carbs. It tastes just like regular pasta and doesn't taste at all like that "whole grain" nightmare stuff. If you can handle that fiber, it's pretty good and will keep you full for hours. Netrition (dot com) carries it.
The Campbell's soup, though, is tricksy. They say it's only 7 grams of carb per serving (depending on what type of "cream" soup it is), but there are lots of chemicals and frankenfood ingredients in that stuff. I'll use it if I'm in a pinch, but every time I read the ingredients I'm flabbergasted at the sheer amount of man made chemicals in it.
When I read Esther's original post (recipe), I had a pork shoulder roast slowly cooking in a 225* oven. I used it to make a low carb BBQ pulled pork... but now I'm thinking what's to stop me from subbing the pulled pork for the pasta? Pulled pork, plus all those other ingredients... double yum.