TNG:
My window and bannister frames (see You are not allowed to view links.
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Login) required that one of the MR-16/ATX combos needed to be outside. I put them into a box very similar to what you described, though without the fancy legs and holes ... it was just an upside-down plastic container sitting on the ground (the irregular space around the bottom was plenty of room for air to get in and out).
The one problem I had was one night the PS just died; of course, it was raining, so I had to turn the box over to reach the switch to reset the PS -- rainwater got on the PS and the MR-16, which freaked me out a bit. But once the switch was reset, the PS took off and the show went on.
For 2011, I'm thinking about relocating that MR-16/ATX combo indoors or maybe building something a little more sophisticated so that I don't have to worry about the rain when/if the PS needs attendance.
The SS hub and PS will be the garage.
HTH.
\dmc