I'm downloading the ZIP now, and I'll jump to the site after I post this, but...
There's got to be a catch. Why would they give the program away for for free for naught but a week? O_o
An interesting fact to note is that, for the most part, the Norngarden series was made in Bryce, so while complex objects are possible, Bryce should not be considered a modeling program and contains no advanced tools for editing meshes. It uses basic Boolean operations and metaballs to form objects.
Does that mean norn breed making isn't recommended for this particular program? What do the 3rd party creators typically use to make new C3/DS norn breeds?