Cream soups are good (e.g. cream of broccoli, cream of chicken, etc), as they're fattier and substantial; plus it's a good way to get your vegetables if you eat cream of [vegetable] soups.
V8 juice is also a good way to get your plants in, as is gazpacho. Smoothies are good if you keep the protein level high and the sugar level low (plain yogurt, whey or soy protein powder, and 1/2 to 1 banana for body and sweetness). Crushed ice helps them taste better IMO--the colder the better!
Hummus isn't exactly "liquid," but it's soft, and you can eat it with a spoon to get some good protein, healthy fats, and fiber. Same thing with yogurt. Puddings and custards are good ways to get some protein in; especially if you use sugar-free varieties or sweeten with sugar substitutes they can be a nice choice for a soft food; especially baked custards. Poached eggs aren't liquid, but they're slippery enough you can essentially cut them up and swallow each bite without chewing.
