i've made bargello's with 14-26 different fabrics---you can use as many as you want. sew your strip sets together- make your tubes- cut your strips then 'play' with the tubes moving them up and down to get a design you like- then open each tube at the appropriate intersection.
if you type 'bargello quilts' into your search engine you will find many many patterns- some free- some cost-some in books.