One of the fun things that I got to do when I was at Mindjet was dream up ways to integrate MindManager with other systems. That's why I created the Mindjet Labs. One of the cool integration demonstrations that I built there was one where I linked MindManager with Visual Studio Team System's Team Foundation Server. You can try it out and download the source code to see how I wrote it. You can also go to a MSDN Webcast tomorrow (1/17/2008) where Terry Clancy will be talking about requirements gathering and he said that he would be talking about the Requirements Manager that I wrote as well (in about a week two years ago).
If you are feeling really enterprising, download the source code for the solution (it installs with the solution), update it to the latest version of MindManager and make it even better, integrating with the Fluent Ribbon UI. If you want to do that and need some assistance, please reach out to me.