So I think I'm pretty screwed, but I wanted to ask for other opinions.

I agreed to join a startup company last october. I said as a condition of me joining, I needed regular, monthly pay. In fact, I was offered the position a month earlier, but turned it down because of lack of funds, and only agreed to come on because my boss claimed to have the investor lined up so that I could get paid.

Well, surprise surprise, my boss basically lied about having the investor in hand. He had a few people that were considering giving small sums, but no where near full funding. I hounded him, and he finally gave me one pay check, the first week of December, "Under the table", according to him. Of course, it was only 2/3rds of a pay check, because there wasn't enough money to pay me in full.

To muddle things further, despite me requesting a contract about 25 times, he didn't offer me one until March. On top of that, the contract was simply unacceptable, and led to a work slow down, and then a lot of animosity, because my boss lied through the entire process.

I have been promised all the back pay, even though my boss has changed his mind about my monthly rate 3 or 4 times. I have ample witnesses to the promises he made, and some actual paper trail that promise to re-pay me from the board of directors, but he flat out refuses to put in anything in writing or to sign anything. He will agree to an amount, and how long I've been working, and then REFUSE to sign a memo to make it in any way binding.

I'm not sure if I can even go to the labor board, because what for several months I considered to be him just being sloppy, now appears to be a deliberate effort to block me from achieving an employment status where I have any rights. I know that paychecks in arizona are due no more then 10 days after the end of the pay period, but, again, I don't think I qualify because he was deliberately trying to keep me in limbo.

Is there anything I can do to keep this from getting really ugly, or is it just time that I hire a lawyer? Or do I even have a case?

You can either see an attorney or file a claim for unpaid wages with the ICA, but not both. I don't see how this is NOT going to get ugly. I'd recommend an attorney at this point.

So I looked into it a little further, and I filled out a W-9 for my work several months ago (and forgot until I was reminded today), but my boss never submitted it to the state. I know in California, an employer has somewhere around 30 days to submit that sort of paper work to the state (so if the state needs to garnish wages, etc). Does this same sort of thing apply in AZ? And does this change my case, because I am more of an employee instead of an independent contractor/consultant? I've heard that there is no such thing as an unpaid employee, ie, if i'm classified as an employee (not an intern or volunteer), I must be paid SOMETHING. I feel like this will force my boss to pay me something, though I don't think it will be as much as he owes me.

Wait a minute. W-9's are for independent contractors; a W-4 is what an employee completes. Which are you? Are taxes (including FICA and Medicare) withheld from your checks? Or, better question, which should you be?
http://www.irs.gov/taxtopics/tc762.html

All along I was *supposed* to be an employee. My original position was CTO but recently was changed to VP of Technology, neither of which would typically be classified as independent contractor positions. In the last few weeks, as things soured, I proposed a memo that would have classified me as a independent contractor, because my contract negotiations were at a stalemate, and I wanted some evidence that I had worked at the company and was due back pay. But beyond that, I filled out the W-9 several months ago, before I ever proposed being an independent contractor. If I had to guess, my boss was trying to make all of us contractors, so that he wouldn't be legally required to pay us until he got more VC money. My boss does a lot of sneaky things like that.

And no taxes have been with held, more because I never get paid. I received $1,000 last year that was, according to my boss, "under the table". I still claimed it on my taxes, but it was before he incorporated the company, and for the most part he is trying to hide my 3 months of employment from before incorporation. I don't know the exact reason, though the general impression I got was that he didn't put me on the books when he incorporated, and to go back and add an expense to the books after the fact is a pain in the ***.

Sneaky, illegal, and a bunch of other things.

You need an attorney. Seriously.:(