Personally, I HATE the look of oak, but since I'm not planning to pick up one of your cases anytime soon (not that I don't admire your work), take that with a grain of salt. If pressed, I'd like to see what you could do in a cherry, teak, mahogany or perhaps even maple.
So far I've tested Maple, Alder and Oak. I've got some Walnut which I'm saving till I've figured out how to cut them properly as this is my personal favorite and I don't want to ruin it, here is a photo of the 4 woods lined up:
I've not been able to cut out any panels from wood with 100% success yet, something has always gone wrong with each one! Which is frustrating as these are laser grade solid wood 5mm panels which are quite expensive.
The problem I am finding is that because they are real solid wood the sheets are basically strips of wood about 100mm - 120mm wide glued together to form a larger sheet, the glue is incredibly strong so the wood will break before the join, however the glue is much denser than the wood and so the laser struggles to cut through it unless you wack up the power and lower the speed considerably, which then causes other issues such as laser flashback and increased smoke staining. I'm experimenting in between trying to get everything else done, so unfortunately its taking some time to get right, but I hope to have at least 1 wood material option available in the next 2 - 3 months.
The Alder is a nice colour and texture, but it varies so much in texture and colour from strip to strip on the same sheet it kind of ruins it (for me), some people may like it though who knows, here are some phone snaps to see what I mean:
Before you call me out for the grain/strips being vertical, this was a conscious decision (just for testing) to get 3 panels out of the sheet instead of 2 panels if orientating the grain horizontally.
The Oak looks good and its difficult to see the join between the strips, this is my second favourite, the tone of the wood works really well with the matte black panels.
The Maple in my opinion looks a little bland and washed out and its light colour clashes too much with dark panels, it doesn't work great either against white panels because the laser cut edge faces are very dark from the cutting process, but again I guess wood aesthetics is a matter of personal opinion. I've not taken any photos of the maple yet.
Cherry is also available, but unfortunately for some reason I missed it off my order.
K888D, since you're looking into the HDPlex stuff, have you considered a complete re-design or new case concept, similar to DAN A4-SFX with the graphics card mounted behind the motherboard, but making the overall case shorter to only accept the shorter length graphics card and maybe only a single 2.5" or just motherboard mounted NVME? It looks like you could get a case down to about 6 liters or less.
I have a few ideas for low profile cases (console style) and would like to pursue them next year, as others have commented I don't want my cases to compromise on cooling, which means they won't be as small as they could potentially be, in the region of 6 - 8 litres would be the target.