There is a place called Metal Supermarkets that sells to the public. All types of extrusions and such. Pretty good pricing. I used to be in the aluminum extrusion business.
They have a location in Nashville.
429 Enos Reed Drive
Nashville, TN 37210
Their website is...
http://www.metalsupermarkets.com/
The only problem you will have is that they will all be raw aluminum and not anodized. Krylon makes paints in many colors that simulate anodizing. I am using #1403 Dull Aluminum in my trailer.
Hope this helps.