Where to purchase wood for BGE table?

I have recently obtained a Medium to go with my XL.  After looking over the present table I am seriously considering building a new one as the BGE XL long table seems a bit too flexible to support both Eggs.  I am still going to attempt to reinforce the present table before making the move however.  My main question is where do you obtain the wood that is used for so many of the beautiful tables I see here and on Naked Whiz' site?  Our local lumber yards just scratch their scalps when I ask about the rot proof, insect resistant types of wood.  Is there a shop/business that has access to these woods that I should check with?