1 egg will just barely set 1 cup of liquid; 6 eggs per cup would be approaching scrambled egg consistency. 1 egg per cup might be workable for an individual serving, pot pie sized quiche, but i can`t imagine how you'd be able to slice a normal sized quiche and not have it fall apart.
i generally use from 4 to 6 eggs for a quiche of about 12 or 13 inches across and filled to about a 1 1/2 inch depth. i use about 2 to 2 1/2 cups liquid.
as far as liquids go, cream will give you a very rich, but heavier quiche. 1/2 & 1\2 is probably more commonly used. personally, i prefer a lighter quiche, and generally use plain, non-fat yogurt for a sour-cream-like tart flavor and slightly reduced fat content.
i don't bake my crusts first.
good luck with your quiche!