Provided that you will be in compliance with all the working clearances in 110.26, you should have no problem. However, there is a minimum height requirement of 6 1/2 feet, which will be taller than the wall that you're going to mount the equipment on, might be kind of ugly sticking up above the wall.
Seems like the easiest & least expensive thing to do would be to use NEMA 3R enclosures & skip building your own enclosure which would be rather large.
[This message has been edited by Tom (edited 07-11-2004).]
Few things are harder to put up with than the annoyance of a good example.