I've read a few that had regional views, but nothing that really stood out to me in regards to detail, food quality or cooking insight. I've been enjoying "Martin Yan's China" on PBS where he is talking about the cuisine regionally on the show, but I don't recall the cookbook having that same info. There is a companion DVD available that includes his travel bits. Perhaps you can borrow that from your library?
David Rosengarten has an interesting view of the history of US chinese restaurants and how there were waves of the different regions coming to the shores of US cuisine. Worth reading. It's in "It's All American Food".
To me, more than regional cooking, starting to grasp the chinese view of cooking is more productive than just recipes of a region. I don't actually believe in the yin/yang or five elements of existance or that food is medicine. But it has shaped chinese cooking and what they serve together. You can download a free ebook that goes into this lightly but interestingly. Chinese recipes and Chinese food cookbook He covers a lot of other ground too. This author also talks about 8 regional cuisines rather than 4.
Thank you thymeless i think oyu might be interested to know i have just come back today from a trip to asia lasting a month , covering malaysia and singapore