Looks like 80x50x5mm baseplate (I dont speak german..). Shoudnt be too hard too make. I assume its made by cross cutting with a dremmel disk and they didnt use a drill first to make holes (like in a #rotor block).
Im thinking of making a similar block for my cpu but I cant decide if channels, like a white water, or pins like this/#rotor blocks, would give the best results. I made a WW clone for my 9700 gpu block with a dremmel which worked well..
Im limited to the same tools you are
Plastic for the top will mainly depend on what you can get.. In the UK theres not many places to buy the right size plastic but there should be plenty in the US. Polyethelene is perfect if you dont mind the block being opaque white. Polycarbonate/derlin etc.. should be easy to get, thats what most people use.
Dont copy the design exactly, you can see from the pics what the mesurements are roughly and that might help make a better block than the original.
One improvement I think would be to make more pins above and below the core esp where the outlets join as there'd be less need for the extra middle top though itd still be needed. It would make it less restrictive + increased surface area (which would still get warm enough to still benifit from extra cooling area).