Interesting on the germination issues. Do you know the varieties you tried? I wonder if they have not been around long enough to make them more stable?
Romanescu broccoli is really interesting. It's a broccoli that has a head like a cauliflower. It is so popular in Italy that it has its own set of recipes. It also fascinates mathematicians since it is a perfect illustration of the Fibonachi sequence in nature. http://en.wikipedia.org/wiki/Romanesco_broccoli