The answer to the question - what plug-in was using to create the book cover - was of course Greeble. For those interested see our Greeble Earth post for the first test render and a link to the tutorial.
So down to the winners, we had so many entries we are sorry only two people will actually be able to get a book - the winners are:
Miguel Martiarena and David Birch, we will be in contact to get your addresses and copy of the book will be put in the post.
Thanks for all those that entered, the good news is that we will have another competition coming along soon :)