newbie questions

Hi,

I'm a long-term investor on the ASX, but I'm interested in doing some playing around with algo trading. I've got a PhD in maths and am a pretty savvy analyst/programmer so I'm looking at developing my own tools for the job. A couple of questions I have are:

1. Can anyone recommend a broker that offers guaranteed stop losses on shares or CFDs?
2. Are there any brokers that offer brokerage on volume rather than by number of trades? Or discounts on brokerage for large numbers of trades?

Any help would be greatly appreciated.