Here you go Lusciouskiwi
Chilled avocado soup
http://startcooking.com/blog/238/Avocado-Soup
It's super easy.
As for an avocado substitute, you might get something texturally similar from a can of chick peas (drained, and mashed). But flavour-wise, I don't know if there's anything like it.
I like the flavour of chickpeas too, they're just different - kind of nutty.