I agree with the advice that you should just use an ATX case. They are a commodity and there are a billion great ones. You'll have to remove the motherboard p

I agree with the advice that you should just use an ATX case. They are a commodity and there are a billion great ones. You'll have to remove the motherboard plate and drill 4 holes for M2.5 standoffs; the full Raspberry Pi dimensions are on the product page, so you can easily print out a 1:1 template, get the right drill bit, and go. No fancy equipment is necessary to drill a small hole in sheet metal, and the result will be very satisfying. I tend to 3D print my own stuff, and have found it to be the be all and end all of electronics projects enclosures. I never had a good project enclosure until I got a 3D printer, and now I always have them. It's amazing! I have at least 3 different Pi projects, and I designed and printed cases for each of them. It's very straightforward and not a bad project for learning CAD and 3D printing. 8 hard drives are going to be heavy and take up a bunch of space, though, so that's why I'd recommend an off-the-shelf case that already has support for that. (Sheet metal bending is the right fabrication technique for this application, I think, and that's how the cases are made.)