It is difficult to find these types of seeds - try alpine nurseries, they sometimes have a variety of hardy succulents, so it's worth a try. Otherwise, there are not a lot around - I think we're onto something...
I'm glad I could motivate and inspire you to try some other crafts, Zanymuse, Bubbles and Lynn - and any time you want some snow, I get lots here.
Seeds can in some cases be shipped between countries relatively easily, so if possible I'll try and locate some more, or harvest my own.