However, some problems were identified by some of the nice people who tried it out in 6.9 Beta. Thanks to Steven C. Buttgereit, Vivek Deveshwar, and Piotr Zalewski, who reported the issues, I can now report that those (particular) issues are fixed!
Go here to download the plugin:
When you click the "Download" button you'll have a ZIP file ending in "GriffonPlugin-Alpha8.4.zip". Install it into NetBeans IDE 6.9 Beta (or later, except that I haven't tested it in "later", so if you can't install the NBMs, revert to NetBeans IDE 6.9 Beta). I've tried it successfully on Windows, Mac (thanks Ken Ganfield), and Ubuntu. The issue is solved by simply removing the dependencies (which were obsolete or could easily be replaced anyway) that were causing problems. Hence, the recurring dependency problems are now a thing of the past in this plugin.
Feedback welcome, as always.