> Perhaps Texas could use a different trading model that doesn't require ultra high speed trading.

What would that model look like?

Suppose we trade infrequently but take orders whenever. A trade is coming up and the order book looks like this:

    buy  XMPL 100 shares $0.40
    buy  XMPL 150 shares $0.22
    sell XMPL 100 shares $0.15
    sell XMPL 100 shares $0.20
    sell XMPL 100 shares $0.25
    sell XMPL 100 shares $0.30

We can always fill the buy order for 100 shares. How much should that guy pay?