I'm interested in buying. I have to know more about how that site was coded however.
The site was written in plain PHP and some JavaScript with simplicity in mind, no frameworks were used.
There is a simple admin control panel that allows you to handle manual deposits and withdrawals. BTC deposits are processed automatically using blockchain.info API.
All database access is performed via a single class that handles string escaping transparently, this dramatically reduces possibility that a programmer might forget to escape some input. So there are no arbitrary SQL queries in PHP - all access to the database is done via stored procedures.
There is currently no support for withdrawal or trading fees. Withdrawal fees can be done manually, and I will implement automatic trading fees for you after the purchase.
If you have specific questions - PM me.