Welcome back to the states Rico! Welcome to NICO.
I'm not familiar with any automatic start/stop systems that can be applied as aftermarket. There is a common thought though that with enough money and know-how, anything is possible. I think, however that the miniscule gas savings you would get from this technology would save you far less money that what you would need to invest in time and money to get it to work.
In fact, from what I've heard, the technology requires more expensive batteries and is really hard on them.. so you'd probably eat up your gas savings in having to purchase and replace the battery.
here's an interesting article:
http://www.thetruthaboutcars.com/2011/0 ... p-systems/
Anyhow.. long story short.. I'm not positive of this, but I do not believe start/stop is a function that can be simply "turned on" by hacking the ECU. I think it requires actual mechanical upgrades to starter, battery and electrical systems in addition to programming in the ECU. The manufacturer would not go through the labor to program the ECU for this if it were not going to be a feature in the vehicle from the start. At this point in time, I don't think there are any "kits" you can buy to DIY either. But, companies like Bosch might be thinking of this for some point in the future.
So.. I wouldn't spend too much time on this if I were you.. But I do like the thinking!