Rob,
I've seen them made into vases, bowls, lamps, etc., like Pastor Bill said (exemplary pics can be seen http://www.daintreetimbergallery.com/catalog/product_info.php?products_id=118 http://www.moreton.co.uk/galdetail.asp?galno=5 http://www.moreton.co.uk/galdetail.asp?galno=6 and http://www.giftlog.com/pp/christmas_her_2.htm). I've also seen some of the smaller ones turned into pens, but there are a lot of voids in them. There's also the wood from the Banksia tree, which has a beautiful leopardwood-like appearance.
Good luck with it, and make sure your tools are sharp!