Thanks for the feedback, everyone.

For the pumps, I'm going to stick to my original plan and mount a foam pad under the base between them and the shelves. I'll be venting hot air out the roof of the chamber, so it shouldn't be too warm in there.

voigts -- I don't know if you've had a chance to run your blades yet, but if not you'll be happy to know that they cut pretty well once installed properly. I cut some pieces with them tonight, and they're turning out pretty good. The blade chews through the aluminum fast. Much faster than a jig as I guess it should be. Left some filing, of course, but after filing the cuts were close to square. So it looks like I'll be cutting metal on the table saw until I decide if I'll invest in a shear or not.