I just found this site called Spoonflower where you upload your own designs and they will print them on fabric for you! HOW COOL IS THAT?! If only I had found this before I ordered fabric for our chairs I could have made my chair project 100% custom. (I am definitely considering it still)
In order to participate you have to fill out a form to be invited to join the site, but once you get your invitation you are free to upload your own designs and order up to three yards of your very own custom fabric. So far they are only offering regular weight cotton but say new fabric options are in the works. Check out the Spoonflower Flickr image pool to see what other people have created from their own fabrics.
I am so excited to find resources like this, I really look forward to putting them to use!