E-commerce Advice

Hi,

I’m looking for some advice on an e-commerce solution using wordpress.

Functionality.
We require a online shop that will allow sales of products to the general public at retail price.
We also deal with fitters that would need a membership area and the ability for them to buy products on account / credit. These credit limits would need to be variable amounts depending on the relationship they have with the company. Also depending on the age of relationship with our company we would need to set different levels of discount on the products we sell.

Is there any solution that can handle this kind of functionality or are we looking at creating a bespoke product.

Thanks in advance