air ride systems?

has anyone designed there own system?i know it wouldnt be easy, but i used to know a guy who made his own system on his blazer, and i dont know how to get a hold of him. i remember it didnt cost him very much and it worked pretty good, and i dont know what would be needed to do this. I was thinkin about givin it a shot but dont really know what all i would need to make it work.