Nice article. Thanks for sharing.
IB's optiontrader wasn't mentioned, but it (synthetically it seems) operates along the same lines. I've entered up to six simultaneous legs into one order and it's gone off without a hitch. I'm wondering what their upper limit is on such a thing...if there is one.
Another interesting piece of optiontrader is that I can't see the real inside bid/offer until after I place the order.