I plan on looking into going to see the director of graduate studies. Ive talked to a couple faculty - the chair of the physics department (who is on my committee), as well as another physics prof (who seems to hold me in high regard). They seemed to give somewhat contradictory advice. The chair basically said that i need to keep working, and that they will make a recommendation regarding whether to continue when they see my work so far (at the end of the month). He kind of acted as though i was fighting to get the experimental work back into the project, but I know how limited time is.
The other professor also said i need to just focus on my theorical, and that I shouldnt be as concerned as I am, since I've already passed my comprehensive exams, and having a student fail after passing the comps would be really embarrassing for my supervisor. Of course i plan to work my ass off, but what worries me is that I still feel like a dont have anything meaningful to contribute. Even I think the work is sub-par.
Fortunately, I have kept a lot of notes about the ongoing issues with him. I've made sure to email myself anytime something happens to make sure its all documented. Some things I was able to get ahead of - like him not talking to me for weeks after i registered my ADD with the university - by talking to people before it happened (in addition to documenting it).
A mediator is a really good idea. We've had somewhat explosive confrontations before, and it always seems to end up with unfounded accusations being levelled at me (eg. its my fault the component burned) without me being able to get a word in edgewise, until i explode and leave.
Thanks for the response though. Its helpful just to read a perspective that isnt knee-deep in the situation.