I have to kill this project. I have no time to work on it, and I can't open the source, so I'm going to let it die. The concepts behind GreasemonkIE are not novel (considering it's a "port" of Greasemonkey), and building a managed BHO is well-documented already. Joe's Apt has a good set of links on this topic, most of which I found independently to help me build a managed BHO. If you're interested in building your own managed BHOs, those links are an excellent place to start.
Hopefully some other enterprising developer can make user scripts for IE a reality, but unfortunately that developer cannot be me.