Showing that there's no evidence for the existence of RLS wouldn't be proving a negative... showing that RLS doesn't exist would be proving a negative, indeed. But you could examine the evidence for something and find it lacking, certainly.
RLS medication (if I'm remembering this correctly) came about in the same way that Viagra did. Nobody set about to come up with a drug to give old dudes boners, it came about as a result of research in to treating circulatory problems... turns out one of the compounds they tested gave old dudes boners and they immediately realized the insane marketing potential. That's just good business.
I take offense to being called close minded. I don't believe I'm close minded at all. I'm skeptical, and I'm intellectually responsible, but that's different than being close minded. Most importantly, I'm very very open to being proven wrong. If you have evidence to show me that shows I'm wrong, bring it on. Please! I'd much rather know the truth than cling to an incorrect belief out of stubbornness. I'm wrong all the time, as I find out frequently from paying attention to scientific progress. I love that part of science, because it means I learn more.
But I do require high standards of evidence. I believe this is only prudent. I'm involved with science on a daily basis in my studies, and I know very well that people are wrong most of the time. Most of the ideas I come up with are, in fact, wrong. Accepting that fact is the first step of intellectual honesty. When you come up with an idea, you have to be responsible to yourself and think "in what ways could this line of thinking be wrong?"
NOT a lot of people do this. More people will come up with an idea then find ammunition to support it. Unfortunately the chances are simply that you're wrong. There's nothing wrong with this. But you need to be honest and poke as many holes as you can.
For that reason I don't find anecdotal evidence convincing; there are just too many ways for it to go wrong. I'm not saying it's impossible for it to be right, I'm just demanding a higher standard of evidence. If someone's anecdote is true, then it will hold up to scientific examination and I will be more than happy to accept it. Really, I will. But I need the evidence. And I think any prudent person should have that same standard, lest those with a desire to screw you (conscious or unconscious) do so.
And if you think I'm cherrypicking, well, fine... I don't think so, but feel free to call me on something if you think I am. I try to be specific when I talk about things, so naturally the specific things I bring up are things I know about, but that's just responsible :P
I've had a lot of beer (if I am what I eat, I'm a pitcher of IPA and a cheesburger) and Superfrog's blocks of text are intimidating, so I'll get back to this in the morning.