I was thinking about doing the same thing with flush mounting my equipment. The rack systems were also to pricey for me as well, I have access to the back of where I want the rack from a utility room and was considering flush mounting wooden shelves that I would build myself, 19"wide, shelves at any height I want. It wouldn't look as slick as a pro rack system, but a fraction of the cost. How much access do you have in the back of the rack?
Brian