Which decaffeination process changes the flavor of the coffee the least? There are many decaffeination methods available:


Swiss Water method
CO2 Process
Roselius Process
Direct Method
Indirect Method
Triglyceride process


(Thanks to Mooz for providing the list I found in his related question.)

Of these various methods, which changes the flavor of the coffee the least?

Bonus question: can I buy unroasted beans of that kind? (That's what I'm really after!)
Based on the article here and some brief experience with roasting decaf myself, I'd agree that the methylene chloride method seems to produce more flavorful beans.  That being said it's hard to make a direct comparison due to the difficulties in getting a single batch of beans and getting them processed for decaf at multiple facilities.  I think your best bet is to find a green coffee seller that you trust and see what they have to offer.