I can saw out the side to put in plexi and as to brackets, welded in place could be a move to kill noise.
Best case I've found so far is the "Stay Quiet" case but it has some issues with the design. For one there's no windowed door and I can't see why that can't be included. (Get it I can't see...hahaha)
Secondly it has some faults with the design, specifically with brackets that are basically welded in place.
Any suggestions? Fan favorites?
Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic