Just once more in other words to really understand, what is possible - is this scenario correct?
1) Use HikaShop for the typical eCommerce processes like payments, cart, vendor administration, etc.
2) Use Sebold to build customized order forms, which exactly looks like how it is required for a specific project and create customized product catalogue layouts
3) Combine everything with one of the typical templates out there like Rocketheme, Yoo, etc. to customize the overall design of the shop...
What you could achieve at the end, is a totally customized shop, right?