New Site/Site Clone

Hi Folks, we basically have had a site that does ok buy could do a whole lot better. We sell DVDS, CDS, GAMES, HARDWARE ETC ETC. Our Site has undergone alot of work, but needs new features. New Features Required: 1. Function that allows seller to sell same product Needs to work in the same way amazon marketplace works. 2. Function in admin that allows us to type product id and it displays products on the home page under seperate category. 3. Froogle Exports We have a large database over 100,000 items so this needs to be able to do this. 4. Exports for all major price comparison sites. 5. SEO The Site gets picked up ok on the search engines but no our products this would be handy. 6. Discount Voucher enabled So that we can produce monthly or weekly voucher for use onlin 7. Onsite Auction So that we can pick special items that the Highest Bidder Wins. 8. Mouse Over Image We would like it so that when the mouse is moved over any Product Image it shows the description in a floating window. We have posted this job a few times and have a few designers pull out on us, therefore due to the hassle involved in recovering monies, we do not put any money into escrow we pay FULL on completion of the job. Please do not bid if you do not agree to the above.