If your client is dead set against anything but granite...you need to work with what is... So look at pattern...herringbone, basket weave, windmill, checkerboard...three out of four use two different colors in these examples and then there are the "random" pattern repeats...Depends on what style you are pushing for the rest of the house...and something to remember, many granites are just as veined or figured, sometimes more so, than marbles....think Red Dragon, Paradiso, etc. Maybe a field trip to a tile supply showroom..or the slab yard for inspiration?

For a visual, type "granite floors" with the quote marks around the phrase in the browse room photo section on this web site and you'll find some photos to refer to.