To finish off Sunday night, I found homes for all the components. First, the vacuum pump and vacuum reservoir. I relocated some electronics that were near the battery (I think it is the starter relay - I'll double-check and, if so, it will be removed permanently):
Second, the power steering pump. This one is tricky. It is fairly heavy (12 pounds) and bulky. I found a place for it along the rack. It will need a rack of its own to hold it in place...
...so Sketchup to the rescue. After drawing a scale model of the power steering pump, I drew some rack pieces around the mounting holes:
Most pieces will be 1" by 1/8" bar stock. The piece on the left is 1/2" by 1/16" box tubing. The bolt on the lower right will go into the main mounting bar of the battery rack:
This is all a little tentative - I need to get some more accurate measurements. But it is a good starting point.