Eggs serve to enrich a dough because of their fats. So anything with a certain amount of fat would work like condensed milk or extra butter or oil. However, keep in mind that though eggs are liquid when you add them to a recipe they change into a solid when they are heated. So if you are adding an ingredient such as milk or oil that does not solidify on heating, you must remember to add a little more flour to your recipe to act as a binder.

It IS a dilemma, but given that THIS post is about quiche - or EGG PIE as we have to call it in this house - and given that quiche needs egg I'm going to gloss over this. Sorry. However, I do feel this a bit lame, and have tried backing an eggless quiche once. The Vegg can be used to make the filling and an eggless crust IS possible, just not as easy to work with. There is a list of egg substitutes here.
I would LOVE to see some of your egg free success stories, (especially the savoury ones) and will test and feature any I'm sent on the Recipe Resource.
Now for the Neocate part....