As a Linux geek, I love what you've done there! And as a licensed electrician, I do have a few suggestions.
-You may want to consider putting a few fuses in place. A fuse is
cheap insurance, and easy to replace if you have a short somewhere. The most logical place would be on the 120v side of your control transformer. There probably is an online calculator somewhere to help you choose the correct fuse size.
-As you mod your pools electrical equipment, make sure you maintain the bonding (ground wire) to the pumps and metal boxes. It should be a solid #8 copper wire.
-Make sure that outlet you have inside your box is on a GFI breaker. It appears from your pictures that it is.
-When we install line voltage wiring in the same cabinet low voltage controls, we try to maintain separation between the two systems, keeping the line voltage wiring in one bundle, and the low voltage in another separate bundle.
If you find yourself making a few custom parts from PVC fittings, you might like this stuff:
http://www.plast-aid.com
It's very strong, and unlike JB Weld, it will
chemically bond with PVC as well a mechanical bond. It sets up very quick, (<5 min) so I cool mine in the fridge before mixing to help slow down the reaction.
Keep up the good work!
Is a SWG next?