Often wondered if buying one of those old 'deco' style wardrobes and thicknessing off the backing to leave the veneer fronts might be an idea.
Lot of work i know, but there are some rare and pretty exotic stuff available for next to nothing, and buying in veneer form these days you either pay a horrific price, or they just arent available any more
I've not came across the likes of what you suggest, in charity shops, marketplace sites,
skips or wherever else.
Not for peanuts anyway, though you could say much of the well made stuff is still being given away.
I came across some old pianos dumped in yards, or dropped into skips with some walnut burrs and the likes, which I've kept, but it's so thin, not sure that it would make sense to make anything from.
Might even be too thin for rosettes for instance.
Best I've found in that regards might be some mahogany veneers on a dresser, thick enough to use for something at about 5mm.
Most other things I've found worth talking about, was headboards & footboards from real Cuban/Honduran mahogany.
I did have a vision to find some rosewood table someday, haha!
Managed to get close and found some super dense stuff, used for window frames of all things, from well over a century ago, and I cannot identify.
It's up to the job for all sorts of guitar components for sure, so that'll keep me happy for a while.
Not touched the stuff yet really, best left as is until the time is right,
much like that Brazilian rosewood, except for the market value of the stuff, of course.
Re-making fretboards out of it, for acoustics anyway, I get the impression that it wouldn't be considered sympathetic or tasteful to some to have that zoot on the fretboard only,
well not at least without the rest of the back and sides featuring this,
if one is going on a traditionally done theme of some kind.
There is much to read regarding that on the OLF, like using that timber for decoration, rather than purpose.
Understandably I would take a guess the electric world is a bit less strict in that sense,
and say it being possible to find a Paul Reed Smith guitar from when BRW was plentiful enough to
buy.
All the best
Tom