Website Development

I am seeking a very able and well experienced contractor to assist me in a new project I am currently working on.
The three main criteria are: -
1. You have a provable record of quality Website development in the area of matching “Buyers” and “Sellers” similar in concept to “EBay”.
2. You have either the ability to “Optimise” the site once live or are prepared to take the responsibility to sub-contract the optimisation to someone who has a proven record. (If sub-contracting your choice would be subject to my final approval).
3. You have experience and proven success in highly targeted “Email” promotion or are prepared to take the responsibility to sub-contract the promotion to someone who again has a proven record. (If sub-contracting your choice would be subject to my final approval).
I am seeking initial fixed price bids and terms of payment based on the above alone.
From that I will shortlist prospective bidders and enter into final negotiation.
Any further information will only be available under the terms of a Non Disclosure Agreement.