Our solution is almost ready to go. You can see it here -
www.onewallet.ioIt's a bitcoin wallet and marketplace combo. You do not need funds in your account to purchase from the marketplace - an external wallet can be used. You can also auto-forward any payments received from selling an item on the marketplace.
All listings are legitimate but it is still relatively early days regarding testing. Please contact me with any bugs you find.
Someone give me some feedback! Also check the pricing by us.. cheapest electronics you'll find!
Are you able to add a section where people can request items or post a wanted ad? I think it would be a good idea as people might not have an item on hand but they could get it and send it to the buyer. So the seller would confirm the sale and the buyer would have to fund an address before the item is sent. It would be hard to determine scams here though because the buyer wouldn't be able to choose who they're buying from. If you feel like adding this it would be a good idea to have options where the buyer can limit the requirements of the seller (10+ Feedback, No negative, No unpaid items, etc.).
Everything is already on Ebay or will end up on Ebay

meh, the fees is so high, but they have a lot of employers and big servers (the maintenance is expensive)... On the other hand, i recommend you try to sell the item in local webs (or in markeplace on this forum) and later, put the item in ebay (if you don't sell before).
They have high financial and marketing costs as well.