Supply/demand can't be calculated automatically: there needs to be a market. If a separate chain is used, miners need to sell domain space. I'd just put the data in the Bitcoin chain and rely on Bitcoin's transaction fees, though.
Merged mining did not created market for Namecoin and while there is demand there is no "supply" because the fees are too low and so easier to squat the .bit namespace by capitalists who want to sell those occupied names for profit. Just like they speculate today with other altcoins.
I wonder why you Theymos was so interested in Namecoin if BitcoinTalk don't use the .bit namespace. Would be great to see a decentralized BitcoinTalk instead one which is "integrated" into CloudFlare.