I don't think it will be as rich but I think it could be done.
Heck, I'm allergic to dairy (along with soy and wheat), so I'm pretty used to making complete dairy substitutions using rice, almond, or coconut milks and it usually works out fine. But that's just me. Posted via Mobile Device
Also if you sub 50/50 for heavy cream, you will notice a difference in the flavor if you have a sophisticated palette, but adding a well flavored broth & some fresh herbs @ the end right before serving will help balance things out.
I usually toss in a few roasted veggies/garlic/onion as an additional flavor boost for soups.