Don't know where you are, but Michaels Craft Store or Hobby Lobby are good sources for precut mats.

My solution was to use a wheeled clothing rack. I had two sheets of peg board cut to size to fit betweent he vertical supports, and used bolts and washers to attach them together. It's good for two 16X20 or four 11X14 prints per side. The rack is only about 36 inches wide - you may want to get a larger one, if available.

I host a forum with over 3000 photographers discussing market and display issues. Feel free to join my forum and ask, because you'll get many different but usable answers to your question. The forum was started in conjunction with our Shutterbug article on selling photography at art shows.

Selling Photography at Art Shows forum

Don't know if you're still looking, but after using
Dick Blick's for pre-cut mats, I recently tried
www.precutmats.com.

I've placed 4 orders from them so far and will
continue to do so. You can order mats by single,
showpacks (contain the mat, board and bag)
and backing boards.

If you don't need the resealable bag, ordering the
the mat and boards separately will be a little
cheaper.

Doug

Take a look at http://www.luminous-landscape.com/columns/art-shows.shtml
I was able to make my own panels by adhering carpeting to a sheet of plywood, then used curtain hooks to hang photos.

Curtain hooks pull on the carpet and the weight of the framed pieces cause it to sag. You can purchase hangers that hang over the top of the panels from ProPanels or from Walker Display. Two of the over a hundred art show resources on my Art Show resource web site.