Okay, Doc. Here is the deal: I don't have a lot of time to write this but I really want to get some information out there. You might already know about Muffwiggler.com. If not, check it out.
There is a tutorial/introduction on modular synthesis that you might find helpful. I think it is poorly thought out, but it is a place to start. The link is here.
There is another thread on Muffwiggler about DIY cases. Lots of pictures. Some I want to point out to you are the ones with no rails. The modules are being screwed directly into wood! Hey. It works. Just a thought. The link is here.
Tell me a bit about what you DO know about modular synthesis. For example, do you know what CV is? Do you know the difference between CV and an LFO? Does modulation make sense? Does audio rate modulation make sense? That sort of thing.
More in a few days...