http://www.bgdf.com/

This does most of what you're talking about, except the revenue generation part. There are other boardgame sites out there which are all about sharing knowledge and play testing - I've been involved in game design myself.

The biggest issue with boardgames is that they are low margin because production costs are so high in low production games. I think there's mileage in ideas like http://www.cheapass.com/ model (kind of like how you described).

I voted against this idea though - I think it will be tough to make money because boardgame designers are such a minority.

Unfortunately, the board game market is pretty dead. People want rich media these days, not board games.

why not apply the same concept to designing new video games?

The boardgame market is not dead - far from it. It may not be as high profile as the video game industry, but there is a strong revival and several new innovative games have done very well.
(Settlers of Catan, Carcassonne, Ticket to Ride)
The other aspect of boardgames is their strong social element, which is why it would be great for a community design effort.

In fact, some video games have been turned into board games (Civilization, Age of Empires, World of Warcraft and even Doom), and games themed on the Lord of the Rings trilogy have become quite successful, for example.

But the important thing is that a breakthrough game that has a lot of support and exposure can be extremely profitable. CrowdSourcing is a way of not only implementing ideas that already have popularity and backing, but of giving them the exposure they need to be successful. It's the Pop Idol/American Idol principle.

It would be a great experiment of the Crowdsourcing principle applied to a 'traditional' concept!

I've changed my vote to +1. Although the revenue model wasn't clear the first time I read this idea (it comes from selling the finished board games), Red3 explained things to me a bit better so I've changed my vote.

I like board games :-)