creating a flr.tile material that looks random

Looking for advice on "how to"create floor tile materials that don't " look stupid" .......

I have plenty of 1 and 4 tile texture images already ...
But am thinking that rotating individual tiles in a paint program
And also making a larger grouping than 4 tiles for the texture file
would give a .. "professional - more random apppearance "

One quick solution that works great for small areas is to find a (texture) image (photo) of mosaic tiles that has
1. lots of the small tiles
2. that are squared & lined up nicely
3. and that has unusally thin and straight grouting lines
and then set the x y values ( texture tab Of Materials DBX) to cover a large area ... or do a "stretch to fit" instead
These then look like larger tiles and the whole floor then looks very real
AND NOT like a COMPUTER GENERATED REPEATING pattern

But am looking for a way to be able to use the regular tile photos
provided by major manufacturers and of course by "Angela"
( thank you Angela )