Other than Texas Instruments and a GP sideview which both have plastic cases, I have nothing interesting to report on case materials. I am always surprised that some manufacturer didn't make a high-end piece trimmed with mother-of-pearl, or some tight-grained wood like coco-bolo,ebony or rosewood. Or just set in a few semi-precious stones. The cases are generally much thicker than need be so an inlay of 1-1.5 mm could have worked fine. I recently picked up a odd Timeband piece that has two inserts of red crystal material set into pockets on the front face - I'd carefully dug them out to polish them along with the crystal when I got to it, but maybe I'll get creative.
Modify a Bulova sideview with the crystal sripe down the top...find one that is well-worn, sandblast the remaining gold plate off, throw away the crystal "stripe", powder coat(baked finish,very hard) the case black and then set in a strip of nice burled wood with a small gold/brass strip along each edge. Yeah baby, just the thing for the chap with a black Mercedes with burled wood interior accents. 8)