I think you may need to bite the bullet and buy on of those very expensive Hammond cases from Farnell,
They have moulded aluminium tops and bottoms. I put a centre piece in mine.
This means you can get at the pcbs easily.Failing that it would be a normal U case from Ebay from Ha5xxx
I was reluctant to spend the money and didn't want to make one, but the Hammond cases are very good and did what i needed