This question about porcelain is a great question. I believe it would be very beneficial to see some studies about the rate that aluminum leaches out of porcelain fillings.

I agree that food can be a large source of it, including baked goods (read your labels).

I have heard of a study (although I have not read it) that says that mixing aluminum with mercury multiplies the toxic effects of the mercury.

Some stainless steel can contain nickel, although I don't know if the kind you're referring to does.

Hope this helps.