I don't think it has been tried too many times in practice, because software binary translation is so proven (eg. like in android x86, or rosetta on mac, or fx!

I don't think it has been tried too many times in practice, because software binary translation is so proven (eg. like in android x86, or rosetta on mac, or fx!32 on nt, etc etc). Itanium is the only one that comes to mind. Any others? Then there are several that have lower level "programmable microcode" kind of level in the hardware, ranging from the Transmeta stuff to mainframe-era writable control store...