Our current payments processor does tax calculation based on the delivery address. The challenge is creating the shop to match up with the product list and get the transaction completed.

I haven't looked deeply at oledrion, knowing the link from the shop to the payments side is going to be the trick, along with getting tax calculated properly.

After exploring a bit more, I am leaning towards Shopify and creating a shop on a subdomain to preserve all the SEO juice we've built up and to ease the full entry to online shop and pay without our interaction.