Since there are a variety of eggplants available in the stores; and the "common" eggplant available now is considerably smaller than they were jus...

I recently had a similar problem with some recipes for baba ghannoush. Had two different reactions...
one, if the recipe author wasn't so specific, we can be similarly relaxed when making the dish.
two, I looked for a standard measure, to get some consistency, or at least a starting point. Found their measure for one eggplant (they didn't say if medium or large, but sounds substantial) was 1 1/4 lb, which gave 5-6 raw cups cubed.
http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2443/2

Hopefully the recipe author weighs in, as I couldn't find her recipe elsewhere on the web, but for the eggplant part of the question, the Cook's Thesaurus says 1 medium eggplant is one pound (see here: http://www.foodsubs.com/Eggplants.html), so I'd say a bit more than that for a large one.