The vintage stereo is a good option. I've seen people install a stereo under the dash in it's own bracket, or in the glovebox. If you do a clean install, it looks just fine cut, but I'd definitely look into your options before you go cutting, and if you do cut, measure very very well, and plan very very well, and cut very very carefully, and it will look really nice. Mine...looks ok.
There's a guy on Yotatech pretty much completely rebuilding a first gen pickup, and he actually ordered some cherry veneer and cut it to look just like what 8T3's got going on with the metal. He's doing it to look stock, but if you cut the dash to fit a modern stereo, then cut the veneer to fit the modern stereo it would look stock and cover up any blemishes or mistakes you made with the dash.