I've attached a new patch "arch-intel-v2.patch" that relects my current 
thinking about this patch.

This adds two new options to the "--with-univeral-archs" option for 
configure: "intel" and "3-way". The former builds a universal binary 
with the i386 and x86_64 architectures, the latter builds one with the 
i386, x86_64 and ppc architectures.

The "intel" build is most useful when your code only needs to run on 
modernish systems, the latter allows you to run scripts on PPC systems 
as well.

Both can be build on Snow Leopard systems. The current options "all" and 
"64-bit" cannot be used when you perform your build and target the 
default SDK because the system doesn't ship with PPC64 suppport anymore.

I intend to apply this patch for 2.7 and 3.2 unless there is serious 
opposition against this. The patch will not be backported to earlier 
versions.