Basically if you want a chargeback system you need a means of arbitrating disputes and this will add a cost to each transaction. It will also require a central authority who has the power to reverse a transaction and it kind of goes against the decentralised model that Bitcoin engenders. There are already Bitcoin escrow services out there you can use to secure transactions at the point of exchange.

I think you raise a good point though and I like the idea of being able to add verifiable meta data to a wallet address (e.g. name, address contact number etc) that bitcoin users can volunteer to give their buyers peace of mind. You could even build in a feedback system so buyers can + 1 the seller and leave reviews that are publicly visible for other future buyers. This may already exist, I have no idea...just thinking out aloud

EDIT ---

I should have read @delaro's comments who I think is alluding to the same sort of thing. Coinbase would be a good candidate to back this meta data with their own verification procedures.