Hi SupremeTrader - thanks for taking part in the thread, it's very valuable with experienced contribution and I hope you'll continue to add value!
THE NEED FOR BACKUP BROKER
You quite rightly emphasize the need for a backup broker. I actually don't have one and I know it is crazy. My venture into seasonals started as a small experiment, but I am pretty certain I will get an account with someone offering pit trades this fall or at least winter. I think finding and dealing with such a (spread) broker could be a good topic in another section of ET

I agree that a pit broker is essential to be serious about spreading, and an essential plan of contingency if the electronic trading goes down whilst pit trading continues (as with energies yesterday).
ELECTRONIC SPREADING
I am quite confident that you're wrong when it comes to electronic vs pit. Everything I'm doing with Interactive Brokers is electronic, and is executed electronically on Globex and ECBOT (and now on ICE with regards to the NYBOT contracts). When it comes to ag contracts I believe it's quite recent, perhaps 6-8 months only, since the contracts where offered electronically.
The way it works is this: Globex and eCBOT actually keep separate (electronic) orderbooks of all possible spreads. Continously the spread orderbooks and outright contract orderbooks are calculated against each other to create implied prices and give fair executions if orders can be crossed. This has been the case with interest rate contracts for many many years, crude oil for a couple of years and it's now happening with agriculturals. It's definitely the future.
FUNGIBLE CONTRACTS
When the pit and electronic contracts are fungible, a member can arbitrage eCBOT vs the pit. If he bids a tick under the electronic market and someone sells to him, he can immediately sell electronically and net the difference. At the end of the day the clearing nets out these positions, leaving him flat. So the electronic and the pit contract are one and the same, just executed at different places. They can be fungible at ratios however, i.e. a big SP contract vs 5 minis.
DRAWBACKS TO ELECTRONIC SPREADING
The drawbacks to electronic spreading from my experience is the lack of liquidity in the backmonths. Not many people bother to quote electronically there, and so prices can be way off or even non-existant. I actually did a spread trade in Hogs this month which was all done electronically - it's kind of hard to believe actually, because the order book was almost constantly empty. I used limit orders of course, and placing them right can get execution from people doing arbitrage.
Another drawback to electronic spreading are the instances where the exchange doesn't support the spread, for instance a Soy Meal vs Soy Oil spread. You cannot quote a spread order, but there are ways around this with software removing a lot of the risk with legging in. (Software at 1.000 usd a month!!!!!!). However, one contract at a time you're only risking 20-30 dollars, and I'm not losing my shirt over that.
SPECIALIZE IN 3-6 MARKETS
When you specialize in a few markets, you obviously get a much better feel for a spread and whether it's "high" or "low" when a seasonal move supposedly should take place. I think the argument for trading many markets is reducing risk through diversification - portfolio style. It's however a lot more work and requires more research.
I'd like to do smaller size with more trades in more markets, but I readily admit I don't know these markets as well as I could. I might come to agree with your conclusion, and would definitely like to hear more about your trading style.
ENERGY MARKETS
No question that these are volatile and shake traders around fast. I think it's ok to trade if you know where to stop out (and have the discipline to adhere to your stop), and it's reasonably realistic to get the stop executed.
POSITION SIZING AND MONEY MANAGEMENT, STOPS
Absolutely, this is key - and the impact is much greater when trading highly leveraged instruments. I've been working on this for the last 5-6 weeks relating to the seasonal spreads, I've got something going here, but unfortunately very little true information (trades and other history) to base it on. I'll describe this in detail in August. I've also got mechanisms for stops and a way to get a timestop - however the timestop is pretty crude at the moment.
NEARBY CONTRACTS AND BROKER FRAUD
I'd be very interested to hear more about this. It's quite often that seasonal strategies end up when the first contract month is the front month or the second one out.
Again, I appreciate very much your comments and hope you'll continue to contribute to the thread! And you definitely should check out electronic spreading - in Corn, Wheat and the Soycomplex it works like a charm.