If this video is to be believed, that's what might be coming. 27:40 is about where the presenter mentions Trader Joe's.
South Burlington has ample options for good food (Healthy Living right next door to this site, Cheese Traders, etc.) but I'd say Trader Joe's would fit right in with their "everything imaginable dipped in chocolate" aisle and other offerings. I tend to make a trip to the one in Hyannis, Massachusetts whenever Kate and I go down to the Cape. We stock up on soap, "Joe's O's," and the aforementioned chocolate. Given that we already don't buy those things at Healthy Living, I wouldn't see Trader Joe's eating into their business much.