I like to use 1 x 4 strips to frame out the pegboard. They also seem to help make it stronger... at least a little less flimsy. The only downside is that you do give up a few holes due to the width of the frame, but depending on the size of your project, it's probably not really that big of deal. Also, in reference to the spacers you mentioned, I have seen them included in pegboard hook accessory multi-packs at Home Depot, Lowe's, ACE, and the like. However, like others have mentioned, there are numerous home-made solutions as well.