Well apparently I'm not the only one who has wished for more interesting miniature floor tile! I'm adding this second post about flooring to include some suggestions from the comments on the last post, as these sources should be on your reference list.
Richard Stacey's Miniature Brick & Stone Products was suggested by Debbie of Tiny Treasures. Their miniature stone tiles are cut from genuine materials - real marble, real slate, real brick - and are offered in several scales. They also have siding and roofing supplies, as well as kits, patterned finishing papers, and peel-and-stick tiles. What I love about their stones is the wide variety - we're not just talking bricks and plain floor tiles (although they have those, too) - they've got cobblestones, "crazy paving," ceramic tiles, pebblestone, genuine marble tiles, large patio pavers, and even miniature curbstones!
The next suggestion, from Rosanna at la stanza di giuggiola, is Le Miniature di Eurosia. This Italian site (translation provided) makes ceramic and terra cotta products, including some nice pottery and garden accents (also be sure and look at their roomboxes and flowers while you're there.) They provide extensive instructions for working with the tiles, and templates for various layout patterns. Their tiles are great - an assortment of plain terra cotta tiles in a variety of sizes and shapes, as well as a large selection of beautifully decorated specialty tiles. They even have coordinated tile sets, with primary and accent tiles as well as borders all picked out for you.