Customizable Pre-Built E-commerce Platform

I am looking for a developer or team who has already built an e-commerce platform with features comparable to Shopify. My goal is to acquire an existing solution that we can customize to fit our specific requirements, rather than starting development from scratch.

Requirements:

Existing Platform: The platform should be fully developed and operational. Please provide a demo link to showcase its functionality.
Key Features: Essential features should include multi-tenancy (for a SaaS approach), customizable themes, integrated payment gateways, inventory management, and user-friendly admin and client dashboards.
Scalability: The solution should be scalable to support multiple users and flexible enough to allow further customization as needed.
Documentation and Support: Clear documentation and support for initial setup and customization.
Next Steps:
If your platform meets the requirements outlined above, please:

Share a demo link with access details.
Provide an outline of the customization process and approximate timeframes.
Include your pricing for customization and any ongoing support you offer.
Only developers with a ready-made solution should apply, as I am not looking to build a platform from scratch.

Thank you! I look forward to reviewing your demos and discussing the potential for collaboration.