I make "cream" soups -- celery is my favorite -- with soymilk.
True, it doesn't have that full-fat thick taste of a traditional cream soup, but I actually prefer them this way, for daily eating. I like the lighter taste.
Just saute some garlic and onion in vegetable oil, throw in the veggies and some stock or water (just enough to braise/steam them), cook until they're tender, then blend it all with soymilk until it's a consistency you like for soup. Salt and pepper (or dill, or cilantro, or chopped scallions, or parmesan, or red pepper flakes, or whatever you like...) to taste.
Yum.