When you refer to a strong focus on sellers, how does this differ to other marketplace type websites, are you saying that other market place sites like Etsy and eBay don’t have a strong focus on their sellers?
I’d argue both of those sites are more about products and categories rather than the actual seller and their portfolios. Of course that’s subjective, but we really want a strong focus on portfolios etc
You should keep in mind that the solutions you have listed above are very limited. They will not preform and scale properly for more or less saturated marketplaces. We have customers from Australia and USA who approached us with similar requests. We suggest Zend (or other similar framework) for PHP marketplace and currently develop one.