Personally, I probably would prepare the eggs the night before, no earlier than that. Big IF though.
I did a little research for you and while I couldn't find a definitive answer for you, I did find the following information:
Is it safe to use eggs that have cracks?
Bacteria can enter eggs through cracks in the shell. Never purchase cracked eggs.
However, if eggs crack on the way home from the store, break them into a clean container, cover it tightly, keep refrigerated, and use within two days. When preparing, be sure to cook eggs thoroughly, with both the white and yolk firm.
What should I do with egg-containing leftovers?
Promptly after serving, refrigerate any egg-containing leftovers.
Thoroughly reheat leftovers and eat them within two to three days. Without tasting them, discard any egg-containing leftovers that have been refrigerated more than three days.
And this link has information about "pooling" of eggs, and while it mostly concerns commercial services, I think the logic still applies here.
http://www.doh.wa.gov/ehp/food/cc-rawegg.pdf
I *think* the reason why Eggbeaters can do this is because it is pastuerized. Not 100% positive, but I think that's the difference between being able to buy the egg whites vs. storing them that way at your home.
Hope this helps a little.