Hi Cal,
I'm probably trying to solve the same (or very similar) problem. Started with FCKEditor and developed some code to convert tags into readable Latex ones...but I've not completed the work because very problematic.
Now, I'm retrying...installed last ruby and rails versions, downloaded CKeditor(thinking's better than FCK) and searching for latex plugin.
How have you solved your project? Have you create the equivalents, finally? I've done many of the equivalents by myself, but some particular cases are impossible to solve for me at the moment.
Could I ask you which features you solved?
Regards, Luca