[support] GAF clone with Drupal

[Giovanni R.]

I'm going to create a clone of websites like GAF (getafreelancer.com)
where people can submit projects to develop and developers can bid on
them in order to work.

Before starting, I'd like to be sure to choose the best way to do it.

How would you build it?

I'd use CCK to create two new content types, Project and Bid.
I've seen it exists also the Node Comment module, and I could use it to
represent the Bids. But I don't know if it's a good solution to do that.

The biggest problem is the reference. I think I need a node relationship
module in order to "link" one Project to many Bids and to display the
"linked" Bids when viewing the Project. A kind of father-sons relation.

I'd like to use URLs like /node/add/bid/123 to add a new Bid, where 123
is the Project nid. I've seen that they exist modules which deals with
URLs, too. (there's a module for everything! ^^)

Which is the best way to implement all this with Drupal?

Thank you for any hint.

Regards, Giovanni

ps. I know there are already plenty of working GAF clones out there, I'm
doing this just for learning purposes, so take your time to answer. :-)