Leave my full time job for temp / contract jobs?

So here's the deal. I am currently way underpaid in my current position. I was just told that there would be no raises this year, and I've been here almost 2 years without a raise. I make about $42k in a position I should be making no less than $65-85k. I have the duties and responsibilities of a position 3 positions higher than my current title. I'm hourly, but I was told if I want to work overtime I can, but I can't claim it.

I was told I am "on the list" for a promotion, but in my mind that doesn't mean jack. It's a small company owned by a gigantic corporation. We've grown 200% in the last two years, with no additional administrative staff besides myself and the office manager, who just put in her notice due to workload and pay issues as well.

SO. I'm considering contract positions, likely through a staffing agency rather than a 1099. I do not need my company benefits, and the 401k contributions are "meh" to begin with. Sure, no PTO, but if I can make 50 to 100% more than what I am currently making, I'll take unpaid time off.

I'm looking at Project / Program Management or Business Analyst positions in IT / Software Development / Semiconductor industry (which are plentiful in my area). I've been getting headhunters asking me if I'm looking, and their starting hourly wages are double what I currently make.

What is the consensus on this? My wife has a solid job that pays extremely well with very good health benefits that covers us both.

In addition, if I do leave my "permanent" position (no job is permanent) for a temporary position that lasts, say, 3-6 months and expires, will I be eligible for unemployment or not? I assume if I'm paying taxes through a staffing agency that I will be eligible for unemployment until I find another temporary / contract position?

What about a 1099? Can I still contribute to unemployment in case the contract expires?

Thanks for the advice!