There are several well-regarded online options. World Upholstery, at http://www.worlduph.com/mb7.htm
has several fabric options as well as detailed instructions if you're willing to try doing it yourself (although their site also has some installers identified). A friend with a Pagoda has had things from GAHH Upholstery, at http://www.gahhinc.com/samplei.html
and has been well satisfied. There are doubtless others, as well. Good luck!