One of my favorite suppliers of curly maple is out of BC Canada. His website is http://www.fine-woods.com. I've never bought directly through his store, but have bought multiple times from him through ebay. He is the best seller I've come across. He even throws in bonus lumber nearly everytime I order from him and the wood is always better than expected. His tops are great as well and at a fraction of the price of some of the bigger suppliers.
I don't know that he sells sides individually, but I've bought some of his neck blanks, resawn them, and then thickness sanded them for sides. I guess that only works if you have the luxary of a thickness sander
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