I modified an Ashdown combo head to make it rack-mountable. I purchased it in a homemade wooden casing which was crap!
10 mins with an angle grinder, another 10 with a dremel de-burring the cuts. 4 holes drilled in the front.
I used the offcut pieces of the casing to add some strength across the top using the existing holes where it mounted to the combo, otherwise it flexed quite a bit.