Dustin,
I have also wondered what was involved in getting on a professional trading desk, and have done a little research. I found a book called "The Fast Track: The Insider's Guide to Winning Jobs in Management Consulting, Investment Banking, and Securities Trading" by Mariam Naficy. It was very informative. It basically covers things like what the positions involve, an explanation of the career paths/salaries and how to go about landing a position. This is a good place to start for getting answers to your questions.
It seems that it is very difficult to get in the field without a degree from a top 20 business school. It is very elitist, and that is why I decided to focus on trading for my own account. With your success I wonder why you would want to go into the investment banking/trading world with the stress involved. Sure, there is a lot of money to be made if you are good, but I remember seeing a post of yours a while ago that seemed like you were doing about as well as you could do at a bank, plus you get to work your own hours. Expect 16 hour days (of course, you may already do this) at a large firm, where taking vacations are a sign of weakness and are heavily frowned upon.
Another thing I've learned is that while institutional traders are talented, they don't have the same skill set developed by private traders. Those guys are not trained to trade directional moves, which is more difficult (in my humble opinion) than market making. They are only trying to make the spread off of customer order flow, which, when you have the advantages MM's do, shouldn't be very hard. They are middlemen and their business plan is built on that. I believe that successful private traders have a much harder job, afterall, how many market makers go out of business? If you are successful on your own, you would be way ahead of many bank traders, and I doubt that a firm would recognize or appreciate your daytrading skills since its a different game for them. They seem to be much more concerned with your educational pedigree. Why not look at a trading firm like Bright (which is like a mix of the two styles) if you are just looking to increase your trading leverage. Your skills would be better utilized at a place like that, and you could certainly make just as much money as the institutional guys.
I haven't worked as an institutional trader, so I may be way off base and someone on the inside could shed a little more light, but that has been my experience when I was job hunting.
Good luck in whatever you do,
Kirk