First of all, you forgot to mention how we encounter this boss. It had better be somewhere remote that you would never stumble upon by accident, like the End, or summoned like the Wither.
Secondly, what does it look like? I need to know how big it is and how it moves. Does it walk on land? Does it hover? Details please.
Thirdly, hard does not equal good. I can't imagine anyone having fun with a boss that can kill you this quickly and easily. All the knockback it does is also extremely annoying. In addition, padded does not equal hard. 1,000 hp? That's five times the health of the Ender Dragon. It'll be a long-winded battle, and once you figure out how to avoid its attacks, it'll begin to just become a boring endurance test.
I will give you some points for fleshing out the boss. I'll be honest, the idea isn't bad, but it needs a serious nerf. That includes the drops. Even if your idea as it exists was implemented into the game, your new armor would mean no more challenges for you in SSP and SMP. The armor should just be one piece that does something unique, but doesn't provide much protection.
Anyway, I give this minimal Support, mainly because I'm an optimist.