Adding support for SFX PSUs is definitely something I'd like to do later on. That would increase the length of the case to over 300mm, including walls, so the biggest obstacle is finding a printer that can print parts that large. That makes it more difficult to find a printing shop but it is not impossible.
For now the material is good enough for a prototype, but I aim for better quality ABS plastic and smoother texture for the product to be sold. The case is lightweight but very sturdy, especially with all the parts installed.
I consider users of Geeek cases to be part of the user group I'm aiming for, since they sell more affordable cases. But there have been issues from customers about the build quality when assembled and ease of use of building in their cases. I feel that my case, while still being plastic, is designed to be more portable and carried around with more confidence than Geeek's.
Right now the Flex ATX layout is similar to that of the ZS-A4S case, and the Geeek A35 which I see is sold in some limited markets. This case supports longer cards than the A35.
The case shell cost me around $40 USD to print in HTPLA, shipping excluded. With better materials such as ABS it would be at least $10 more. Finding a shop that would print large single pieces has been hard for me in the past but I managed to find affordable ones within my budget!
I plan to sell the .stl files, along with designs for side panels, $8 will be the price point. The panels can be laser cut from many materials or also 3D printed.
