I understand you are going to start the project with the feature set that you need. But are you really going to leave out the mylyn trademark functionality? The context sensitive UI/Project display thingie (can’t remember technical term).

As far as existing open projects that have some of this functionality, this is what I could quickly dig up.

Wiki Editing:
http://www.meadowy.org/~gotoh/projects/trac-wiki/wiki

(I was getting 500 error here, so this is a google cache version)
http://64.233.183.104/search?q=cache:CVr6zmfpEjcJ:www.meadowy.org/~gotoh/projects/trac-wiki/wiki+trac+emacs&hl=en&ct=clnk&cd=1&gl=us&client=firefox-a

Wiki editing is probably the most complex thing on your list. As working with tickets TRAC has a pretty accessible API we can use to give you that functionality. That part should be pretty easy to do. I guess building a suitable CLI for that module would be the interesting part. Maybe we can find some inspiration in goosh? I know modern versions of emacs have more UI/graphical prowess then I give it credit for, so it should be possible to do something like that.

Looks like you have management of tasks figured out.

Sounds like a cool project. I am a lisp illiterate, but let me know if I can help out in any way.