http://lightning.network/lightning-network.pdf
The oracles have to stay on-chain, but the LMSR markets can go off-chain.
Instead of having to wait the blocktime for trading, they will be able to trade instantly.
Instead of paying a fee for every trade, each user only pays one fee upon signing up.
Instead of putting every trade into the blockchain, only the net result of the off-chain market on each person's balance is recorded.
I saw that on r/bitcoin ... very cool.
The concept of batching the trades is what I was thinking of in the Excel sheet tab called (I think) "Some Accounting". It works along similar lines...batching the trades somewhere else and then submitting big updates. ( The math checks out, of course. )