> I am running Windows Vista x64 and would like to set up an x64 build of BIND
> to mee it seems that if a *nix x64 build is available for quite a while, a x64 Windows build should be possible.
Sorry, that is irrelevant. Either you are misunderstanding things, or
then I misunderstand what you mean.
The question you should be asking is whether the software in question
has been ported to 32-bit Windows. If it hasn't, then the fact that it
can be built on 64-bit Unixes has little significance. The difference
between Unix in general (32- or 64-bit) and Windows in general (32- or
64-bit) is much larger than the difference between 32- and 64-bit
Windows. If some software is reasonably portably written in the first
place, and it is portable to 32-bit Windows, then the additional steps
needed to port it to 64-bit Windows, too, are usually not that hard.
The API is after all the same on 32- and 64-bit Windows, just the
sizes of some data types are different.