This is my belief of how a p2p-exchange can be built, after 2 years of experience with bitcoin, mtgox and all speculators and scammers...

Requirements
It must be 100% open source
Early adaptors must not be rewarded
The dev team should not be greedy, our reward will be fame, not money or coins
Assets and Exchange as two separate projects

Asset Coin
We need to create a new alt-coin for the sake of a public ledger of assets, "AssetCoin"
This coin will use Proof-of-Stake instead of Proof-of-Work to save energy.
The inflation must be high to prevent hoarding, Each contract (coin) should never cost more than 1 cent.
Instead an empty contract can be signed by an issuer with an IOU of an asset, for example BTC-E issues 1 BTC per contract.
The domain assetcoin.org is not free, so we should call it something else.

P2P-exchange
The exchange must be created totally separate from the "AssetCoin", this exchange will run on torrent-data and distributed computing.
Anyone can participate to run an exchange node for a certain exchange, each exchange is totally separate from other exchanges.
All nodes will equally share the transaction fees.
Exchange fees are paid with a certain AssetCoin, for example an IOU of USD issued by Western Union.

As a client you could for example by a USD-IOU on the street and begin to trade on the p2p-exchange and buy GOLD-IOU.
Your assetcoins will always have an intrinsic value, the value is guaranteed by the issuer.