WordPress Multi-vendor

Hi everyone,

Before I start, I do appreciate that this has been asked a fair few times before.
However, I’d like to take a different approach to the problem, and break it down.

Here’s what I’m looking for.
I am in the process of creating a website similar to Turbosquid.com (yet simpler), but focused at the community of developers using the Multiverse MMO Platform (which is currently going Open Source).

I’ve worked out the theme, and I’ve created a basic template for products. The main issue now, is how to sort out the financial side of things.
At the moment, the test products I’ve uploaded are all free, and all you need to do it click the download button and it will download. That’s fine.
Ideally, the logged-in user would go to the product page (let’s say, a 3d tree model), and click the Buy button (assuming it’s not free).
When they click the button, they will be taken to a PayPal transaction page, where they will fill out the necessary details, and the payment will be sent to the seller. Then, some sort of unique expiring download link will be sent to them by email, and they’ll be able to download it.

Now, here’s what I think can be done.
Each seller has the equivalent of an Author account, which allows them to post products etc. In their profile, they can add their PayPal address, so when the customer buys the product, the transaction is between the seller and the customer. For the moment, I will have to get the seller to send the download link, to the file which will be hosted on the site. Later on, however, I will code in the PayPal notification system that ZenCart uses, and get it done automatically.

So, what I think I need to do (assuming it’s even possible), is to add a field for the PayPal email address, then find a way to automatically link the Buy button to their PayPal account.
Is this possible?

Any input is appreciated!

Thanks

Tristan