Long ago writing VBA macros for MSFT Office was part of my job.
Now it looks like I may be traveling down that road again, and I have not touched MSFT Office for anything serious in years.
Is VBA still the de-facto standard for creating msft office extensions?
Is it possible to write (non-second-class-citizen) MSFT office extensions in any language besides VBA yet?
Macros are still good for prototyping. However, since they are an easy attack vector for malicious code I would try to avoid them for wide use. Have you consider Visual Studio Tools for Office as a platform?
The "state of the art" is to use a .NET language for Office development, using VSTO. This is typically done via C# or VB.NET.
My take on this would be to integrate VSTO and IronPython. We have made several solutions with this combo and are very happy with it. It enables you to write core parts of your solution in C#, but at the same time have a flexible environment to customize your application.