Printing my own 12 x 12 paper

I'm wanting to print my own 12 x 12 cardstock paper. I really want to have the design to be matte like Graphic 45 and other cardstock papers. Printing at Staples limits me to 8 1/2 x 11 and a satin/gloss finish. Has anyone tried other printing services and were the pages matte like Graphic 45? Any advice is appreciated.