Yeah that's definitely a thought. I can only image the work it will take to design a riser of my own (either that or pay a bunch to get someone else to do that). Right now I'm working on refining the design into a more console-sized package.
As QinX said, if you want a rigid riser, either talk to him or take a look at some of the readily available ones.
Don't even start to think about designing a flexible one for yourself! If you don't have experience with high frequency applications and EMI shielding, it's going to take you forever. I tried to design a decent front audio panel for my case and put that on hold because it was too complicated when signal quality was factored in.
LiHeat is indeed the way to go because they make custom length risers even in small batches and they aren't as expensive as 3M.
Of course, the cheapest riser is always the one you don't use.