This is a great idea. I would definitely try it out.

I'm pretty sure all parents have this concern especially when the doctor asks whether our place have lead and have no idea how to answer them. This is especially the case in the Bay Area where houses are old and is within the time frame of lead paint.

Several concerns here though. How hard is it to test for these things and how much would you charge the customer? Usually lab work are expensive and might not be within the price range.