I am not sure about the market research company, I am sure someone will come forward to help you.
Just my two cents when you develop your site don't hire a developer to do it - unless you are an extremely busy person. Use services like shopify.com and work on adding and creating your own catalogue website. They can handle payments and everything. There is also a new service from Google called Home which can help get you started. Starting is very easy and requires minimal investment - so you can actually just go ahead before a market research and see how it fairs - that way you will get first hand experience.
2nd December 2012 From India, Gurgaon
2nd December 2012 From India, Hyderabad
You should also take a look at deviantART: where ART meets application! - its a community of artists and art sellers. From what I can see it seems the story behind the art, the artist and the photographs would be the most important to make sales online.
3rd December 2012 From India, Gurgaon