so I can do:

$ setarch i686 
$ strace -s8192  -e trace=execve /usr/bin/python
execve("/usr/bin/python", ["/usr/bin/python"], [/* 65 vars */]) = 0
execve("/usr/bin//32/python", ["/usr/bin//32/python"], [/* 66 vars */]) = 0
[ Process PID=3559 runs in 32 bit mode. ]
Python 2.7.1 (r271:86832, Apr 30 2011, 13:29:12)
[GCC 4.6.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
$ strace -s8192  -e trace=execve /usr/bin/python2.7
execve("/usr/bin/python2.7", ["/usr/bin/python2.7"], [/* 65 vars */]) = 0
execve("/usr/bin//32/python2.7", ["/usr/bin//32/python2.7"], [/* 66 vars */]) = 0
[ Process PID=3571 runs in 32 bit mode. ]
Python 2.7.1 (r271:86832, Apr 30 2011, 13:29:12)
[GCC 4.6.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>

This is necessary because the 32-bit /usr/bin/32/python*'s PYTHONHOME is /usr/lib32/python2.7 , where 32-bit shared library python modules
are installed under lib-dynload/, while the native 64-bit's /usr/bin/python2.7's PYTHONHOME is /usr/lib64/python2.7 which has 64-bit 
libraries in lib-dynload . The 32-bit python uses /etc/32/ as its
$SYSCONFDIR .