Multi vendor website

Hi,

I am planning to develop a multi vendor website (something like Etsy.com). If you have done similar work, please get in touch with below information

1. URLs for previous work (multi vendor work only please)
2. Technology used (Php/Java) & full stack details
3. Would you be comfortable in developing a solution in Php/Java. You are free to choose an existing product (Ex: Magento)
4. Cost (Plugin/Addon costs if needed) & time estimate

5. Can you provide support after Go live for long term? If so what is your rate and availability?
6. Interested to sign NDA?

Thanks for your time.