I think I'll have to prototype a few key bodies.
The local Rona (well, when I get back home from travelling) has a good selection of veneers. I've got a nice sheet of oak veneer, but it's been delegated to a study desk for my SO ^^'
I might still just go with stained pine sealed with shellac or varathane.
Instead of hinges, I'm thinking of rollerblade bearings on individual axles. Not sure what to do wrt springs. Part of me wants to try and use neodymium magnets, I know it sounds like over-design and fraught with caveats, and it probably is.
It's always nice to dream how perfect you could make your device, but going for some prototypes of key bodies is definitively the best and if they work out you could think about veneers.
Your thoughts about using aluminum frame are good since it's really rigid, but it might be lot of work at the end with lots of screws and you also have take in account, that all the threads has to take some mechanical stress etc.
Since you are eager to start making and I'm not ready with a conclusion video I give you the hints in textual form:
Wood is at least best choice for prototyping, but I would recommend using fine grained and really long seasoned wood too be sure I keeps its shape. Take the grain alignment into account since the longer the piece the more it will extrude bend or even twist with changing humidity. Even perfectly measures and manufactured you pedals might stuck at the end.
Noise is the biggest problem I have with my pedals. I didn't think about that at the beginning. I would recommend to build the pedals as light as possible and just as durable as needed. Inertia really matters at this scale. Lighter pedals also allows you to play faster if you like. That's why I also liked the idea with aluminum pedals with some wood on top.
The springs has to be scaled correctly. They has just be strong enough to push/pull up the pedals with some margin to wear out. If they are too strong the will thrust the pedals against the upper damping and cause noise. The damping has to good enough. Felt or leather might be sufficient.. I tried to mold conic silicone stoppers which work well, but they shrink after the molding and I didn't have time to address this yet.
Your roller blade bearings idea is also good, since the aren't that expensive and it will keep at least his part silent. I'am also planning to use them for my robot arm project (which will be molded from aluminum)
Individual axles are nice, since you use an arbitrary order for the pedals like an arc and with different levels, but consider it to be a lot more work.
Will you build a full scale one like that one form the link above or one with short keys?
No matter what you do plz document your work. I can't wait to see the result