Advanced trading features

I'm a programmer, and have been trading BTC for a while now. I'm quite disappointed with the features Bitstamp and BTC-E provide, but since they have APIs, I thought of implementing a few useful features. Just want to hear your opinion, whether it would be useful to the community. These are mostly automation ideas.

1) Buy if have money / sell if BTC is available.

Currently you can only post a buy order if you have enough money right now, and you can only post a sell order if you actually have that BTC.

2) Buy/sell X amount if the market touches price X.

This can be used to automatically protect against crashes. Currently you can't post a limit sell order at a low price, it will just execute instantly and you will lose money.

3) General flexible tree-like trigger system. Imagine you could stack rules that would trigger other rules. For instance, you could do

If the market price falls below $1000, trigger the following:
A) Place a sell order of all BTC I have
B) Place a buy order at $900 for 1 BTC
C) Place a buy order at $800 for 2 BTC
D) Place a buy order at $700 for all the money I have available

This particular scenario protects you from flash-crashes that bounce right back.