Ask HN: Any tips on finding relevant Shopify/Magento store owners?

[dmagriso]

I'm looking to validate an idea for a service targeting online fashion stores. Would like to get some feedback from Shopify/Magento owners. Any tips on finding the biggest stores on a platform?

[moepstar]

Looks like this could do it: http://magento.com/customers/customer-showcase

Surely, other platforms have similar sites.