I've been wadeing through this thread that is the ultimate source for bean information. @rancho_gordo Paula Wolfert, and Russ Parsons all contributed a lot of advice. I've only gotten to page 5 of 14 and I have learned a lot. They covered just about everything that we have talked about. From salting the beans, adding tomatoes and the advantage of using a bean pot.
@Shel_B I think if you read far enough in this thread you will find your answer to getting a thicker, richer pot liquor.