Hi,
Good Day. I have read and understand your requirements. You want to provide a platform where sellers come, register and upload their products. You will promote them. Customer will come browse your site and buy products. For custom or missing products they are send a request. The earning of this site will be subscription fee.
We are ready to work for you. We have a good team of Graphic Design, HTML, MySQL, PHP, Website Designers. From last 10 years We are working in Development fields. We will deliver you the best solution which you need it. We are flexible with our timings.
Hope to here you soon.
Thanks