I didn't mean .NET in general, I just meant .NET support for ports of existing open source languages like IronPython and IronRuby.

Admittedly, I don't really dabble with the .NET ecosystem much, but when I had to use SQL Server Reporting Services for a work project and we had to create a custom data source, we had to write the component in C#, it didn't support other .NET languages (I think it also supported VB.NET, but yeah, no thanks). That would have been a logical place to allow for extending their code with a language that I was more comfortable with.

There's also the ignored opportunity to provide better scripting in their Office offerings. While Resolver One is a really cool idea (spreadsheet built and scripted in IronPython), what I would REALLY love is to be able to call IronPython from Excel, but it's probably not gonna happen.