If you can do this, I'm interested in buying.
If you want to try something a little easier initially, my other suggestion would be just a single cut-out, not a patterned cut-out. Or, make the design three-plate; a top plate that's a square or rectangular cut-out (clean and easy to do), the center plate which is much smaller and big enough just to block the cutout of the top piece in all gears, and then a bottom retaining piece that is cut gated. In fact, if you make this part very cleanly, it gives the purchaser the option of choosing either the single opening or the gated look, since you can just swap the top or bottom plates--and, it saves you on cutting, since you'd only have to cut a gate pattern into one of the plates; the bottom plate isn't visible anyway, thanks to the center plate (the plate the locks onto the shifter and slides with it).
Does my description make sense?
-Ed
