Good Bloomburg report on the vast wealth at the top end of the National People's Congress here. I'm disappointed they don't have statistics for the median NPC and median US Congress level, though, which I suspect would look a lot more even.
The NPC is probably the least meaningful way in which the super-rich exert power, though; it's icing on the cake, plus, as Victor Shih points out in the article, an extra layer of political protection. The NPC very rarely does anything in the way of actual lawmaking - hell, it only meets for 2 weeks a year, and the members aren't salaried. The Chinese People's Political Consultative Conference, its "advisory" little brother that meets at the same time (the "Two Sessions"), does even less.
So what actually happens at the Two Sessions? Well, it's essentially a big conference. So like any effective conference, academic, NGO, business, all the actual meaningful work and decisions have been arranged long beforehand. So the members basically behave like attendees at any conference.
They network, and catch up with old conference buddies. It looks good on their CVs. They use it as a junket and skip the sessions to go sight-seeing. They use it as a platform to promote their worthy causes or crackpot views. Want to argue that the moral decline of Chinese society is because of the abandonment of the eight-legged essay? This is the place to do it. They find out about new sources of funding, and work out business deals. And they get the chance to access the center of power; the geographical and political distance to Beijing is still a vital part of Chinese politics.
The one thing that doesn't happen often, as far as I know, is conference hook-ups (hookers are a different matter ...), not least because only about 20 percent of the delegates are female. Though I do like to think that for at least some secretly gay members, the Great Hall of the People is their Brokeback Mountain.