If you wish to build your own, it can be "made to fit" what you want. If you take a look at places like Guitar Center or Musician's Friend, or All Pro Sound online, you can find "rack rail", "rack screws", and "rack shelves" for reasonable prices. I would recommend using all of those, and especially get a rack shelf before you build it, so you can get your side to side spacing right. The rack rails save a lot of pain trying to make your own, all you need to be do it mount them at exactly the same height on both sides. The rack screws are made especially for the rack rails and equipment you would mount, as rack rail is already tapped for the screws, eliminating the needs for nuts on the back. Another thing, plan for ventilation. Maybe leave it open on the back, or put a mesh panel or two in it, and even some fans if needed.
Here is a page describing rack dimensions. (
http://en.wikipedia.org/wiki/Rack_unit) The music stores commonly carry the 19" wide stuff (which will mount equipment up to about 17-1/2" wide). 23" wide stuff is more of the commercial flavor, and more expensive. One thing to remember on rack shelves, if the equipment is heavy, by a shelf that is taller, i.e. 3 RU compared to 1RU. The sides will reach further back, and be more robust.
Good thing about building your own, is you can build it out of metal, wood, etc. You can make it look like a piece of furniture, put doors on it, etc.
Hope the info helps.
de NA4IT