I think BTCJam has already a similar loaning system, you only give out loans based on reputation and requirements, perhaps collateral.
is very difficult for get loan in btcjam, I've done the paypal verification, verification of documents, etc. but I still can not be trusted
the p2p lending system has to make a few changes, maybe by creating a assets backup system where a user can send a neutral party an item or something of value to say this person is backed up by this and this.