Thanks for the feedback so far. I have one Nording already, a Grade 3 in a dark brown - probably of similar quality to the Signature series. It's a fantastic smoker, though the briar does have flaws (as you'd expect from a Grade 3).
I like the idea of the pipe "maturing" with use - seems to me the whole point of an unstained, unwaxed pipe.
I have seen one photo of a well-used Signature, and it has taken on quite a different hue from when new, and that does appeal to me.
So I'm thinking maybe another Nording, and not another Pete.