You can access the VBA object model from Python once you've got a COM conduit. There are a few Python libraries to allow you to do this; you'll be able to write VBA-like code in Python accessing Excel's internals in a similar manner. Debugging can be a bit painful though. I've done this both from Matlab and from Python, and it's fine for smaller projects, writing structured/formatted Excel workbooks, etc.

I agree that Excel as a GUI can be phenomenal.