Sounds tastey...but I don't think it would work as well. There is a lot of oil in avocados, but there are other things in them, too, which your body would be expending energy to digest.
Did you try shaking the olive oil and lemon juice together and drinking it? I have read that this makes it easier to get down, as does drinking it through a straw, holding your nose while drinking it, and rinsing your mouth with something to cut the oil afterwards (but don't swallow it!).
I've also heard that other oils...flax, almond, etc...can be used in place of olive oil provided they are cold-pressed and organic.