Are there any DP members with sites established that actually generate millions in revenue rather than the thousands that we hear so many people talking about?
Yea, people usually keep it quiet. Those who brag about their earnings usually don't earn half as much as the guys who keep it quiet.
just remember, if you can't make it yourself, you can always marry one http://www.millionairematch.com/
They are definitely out there. I have a site that's doing well, but I'll only ever publicly discuss sites/projects that I'm working on. You have to remember that if you post a topic with "my site makes millions every year and here's proof", two things will happen; - You won't be taken seriously and people will assume you're trying to sell them an eBook of some sort. - You'll be swamped with PMs asking for advice.
I'm only "bragging" right now because I make about $10 a day. Once I make the millions, I'll stop talking.