combining a C# GUI with Python code?

[James]

Yes! It is. Just make your GUI in C# and assign event handlers using
Python for .NET
http://www.zope.org/Members/Brian/PythonNet/

Python for .NET is a great tool and has a minimal learning curve.
Unfortunately, it hasn't attracted enough attention from the Python
community. It does not have a .NET 2.0 release yet but it is in the
works.

Or you could use Boo with SharpDevelop. You will get Visual form design
with a very Pythonic language. But you won't get to use Python
libraries.

IronPython is getting IDE integration in the CTP releases for Visual
Studio. Maybe it will support form design in the future. I have not
tried it yet.