You think it will take more than 650 hours to build that?
Seems like 40-80 hours to me. After you find some well-written PHP forum software that already uses PostgreSQL, you just need to add the dozen or so major required features and then some minor required features that will probably take less than an hour each on average.
The forum will probably have at least 100 more BTC by the time I start thinking about ending bidding.
What do you mean "find some well written PHP forum software"? I can't think of any forum software, free or commercial, that wouldn't have a license agreement forbidding you to modify and sell/resell it.
And you've obviously never written a line of code in your life if you think 40-80 hours is even in the ballpark for this project. It's the construction equivalent of expecting someone to build a house in an hour.
I don't think the intention here is to sell or resell it. He wants it created for this forum. I doubt there's any licensing issues to worry about as far as that goes... but yes, it's a pipedream at 80 hours under any circumstance.