I cannot reproduce your issue.
I'm on Lion with python port installed with universal variant and py27-numpy built for i386 architecture. Check following output:
~ $ port -v installed python27
The following ports are currently installed:
python27 @2.7.2_4+universal (active) platform='darwin 11' archs='i386 x86_64'
~ $ port -v installed py27-numpy
The following ports are currently installed:
py27-numpy @1.6.1_1 (active) platform='darwin 11' archs='i386'
~ $ port select --show python
The currently selected version for 'python' is 'python27'.
~ $ which python
/opt/local/bin/python
~ $ python
Python 2.7.2 (default, Jan 16 2012, 17:34:25)
[GCC 4.2.1 Compatible Apple Clang 3.0 (tags/Apple/clang-211.12)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy
>>> ^D
~ $
