Second, you read my mind. Modularity is almost a core building block of the opensource structure, and necessary, I think, if ASIC mining rigs are ever going to become truely open.
Third, I would like to ask that you publish your CAD or Model files for the community. I know it's a lot to ask of anyone who wants to make a profit off bitcoin, but it's a step we all need to take if bitcoin is going to be what we all hope it will be.
I did not use CAD to design the model unfortunately, I could provide an FBX model however as this is a visual concept not much can be done with the model as it is. When I create the re-design I will probably work in CAD then I can provide a detailed schematic. I have lots of projects so this is just a wildcard idea, I don't expect this to go commercial unless I get lots of demand, enough to source a manufacturer atleast lol.
The open design looks to be great for cooling, designing something vertically stackable will prove to be difficult, as experience has shown that leaving the top of the video cards open, helps a lot with the heat. Modular design is nice, but unless you want to go big, and design your own circuit boards, not really seeing it happen. Best is to stay with the E-ATX formfactor for mobo's, and keep max length on video cards in mind. (every modular block will be mobo + GPUs)
The other problem I see is the price, though I love it and it looks really pretty, buying no case is cheaper than buying one(as preferably you don't want a case, to give your cards maximum amount of air), and this one in particular looks to become an expensive one.
Designing one with extreme airflow for budget price would generate a lot more interest. (simple custom case for under $100, with a lot of fan options, especially aimed at multi GPU setups)
I will take this on board, I did not really design this from a practical perspective, the chrome pipes for instance were random purely for aesthetic although I guess they could function as some form of cooling system . How much space would be required vertically to reduce heat? I am sure I could design a nice rig set up that stacks vertically and has space, I will definitively go for something more economic and reaistic. I assume the power supply should sit at the base.