In Texas we have as many homes with tile/stone flooring and my company, Centex Green, picks up these jobs in addition to carpet cleaning. The issue has always been getting a good treatment to preserve the clean and maximize profit.
Following 2 years of development and testing Centex Green is selling NSWR 500 Easy-Cleaning, Invisible, 0% VOC stone and tile treatment. It's been doing well on the job as well as at the jan/san stores and now I'm offering in on line. Check it out at http://www.centexgreen.com/products-carpet-cleaning-products/103-centex-green-nswr-500-easy-cleaning-invisible-0-voc-stone-and-tile-treatment
I've even used NSWR 500 on exterior jobs and it works great on stone/concrete patios - great way to pick up some $$$$ this spring. Believe me customers will love it and they'll tell their friends.