Custom Vbulletin Site

My idea is to have a community website that will have offer several categories in which people can review and discuss products. The really big part that I want to boast, the part that will make the site unique is that we want to offer safe, buying and trading of paintball equipment. I want users to be able to post their paintball equipment that they want to trade or sell in one of these categories, but at the same time have an option that will allow them to use us as a 3rd party moderator of the trade or sale. Example: User X will post his product and User Y wants to buy it. User Y would send us the funds, we would then inform User X that the funds have been recieved, user X would then ship out the product, once the product is recieved by User Y we would then send User X a check in the mail. We also want to offer secure auctions, in which we will use the secure sales method that we had mentioned earlier. We will also need some kind of advertisment rotation system implemented into the site. The site will need to have 2-3 ads on the screen at all times and each will have to rotate. Let me know if you think you can do all of this. It would really be helpful if you have some kind of examples of your work that we could see. THE REAL BUDGET IS $50-$800