It took me a while. IronPython is no longer available as a Debian package so I had to build it from source. Here's the result:
IronPython 2.9.9a0 (220.127.116.11) on Mono 4.0.30319.1 (64-bit)
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> import sys
Does ironpython still run on Mono? What does it report when running under Mono on non-Windows platforms?