As the Microsoftie in this thread I feel compelled to point out that you don't need an extensive partnership with us to integrate with office.
And I'm not talking about the plugin development hell (never had to work with it, but that seemed, erm, "difficult"). Feel free to reach out to me if you have questions, or just read the docs yourself (http://dev.office.com/).
Quick question: why aren't there any code samples [0] in C/C++? It would be nice to at least have a documented C++ WinRT API to work with for those of us that still write native desktop applications/services. I'm sure other folks across the company would agree ;)
Take this as my own personal opinion, but before I went back into engineering, I worked with a bunch of developers out there to integrate with all kinds of our stuff - and outside of game development, C/C++ isn't the most popular choice. We have some code samples [0], but I see what you mean.
The office team moving away from the old plugin model and opening up the gates for JS apps and REST APIs made life dramatically easier for a lot of folks. So I assume that samples were written with the most popular choices in mind. Internally, C++ is king [0], of course.
It's also worth pointing out that we always accept code samples from the community :)
And I'm not talking about the plugin development hell (never had to work with it, but that seemed, erm, "difficult"). Feel free to reach out to me if you have questions, or just read the docs yourself (http://dev.office.com/).