A third edition of The TRIPS Regime of Trademarks and Designs has now been published by Wolters Kluwer Law & Business. You can check it out on the book's website here.  The author is the ever-industrious Nuno Pires de Carvalho and, while the book inevitably contains more content on the trade mark side of things, his attention to designs is welcome -- particularly when one recalls how little is actually said in TRIPS itself about designs. 

The book's contents can be viewed here and there's a sample chapter (58 pages on the primary functions of trade marks and designs) for your inspection here.