Yep.

Lior Yaffe (I think it's him, "lyaffe" at Stackexchange) has answered my question at Stackexchange. The main problem being that currently Contracts are not allowed to be triggered by phased transactions, but if I interpret his answer right then that could be changed. And a small enhancement of Phased Transactions would be required, too.

I'll soon write an a bit more detailed answer to Lior at Stackexchange - it seems that I misunderstood something about Phased Transactions (because I thought they worked more like Bitcoin's scripts), so I first want to ensure I understood it right now re-reading the Phased Transaction description.

If you ask me, if that could be implemented (and it looks so), that would be tremendously bullish