Zen Cart is perfect for part of my project, but I'm wondering if I've missed a module that will do the rest. If not, does someone know of a 3rd party script that will do what I'm looking for:

Without giving the plot away, say my store sells news articles. The average price is 50 cents. Authors can submit multiple articles and they're displayed on a Zen cart style store. (That part can be manual)

Customers lodge a $20 payment, then select as many articles as they like over time to the value of $20. A bit like a membership site I guess.

Sales are then credited to the different author's accounts, less a fixed commission. Sales are also transferred to the Author's Paypal account on a weekly or monthly basis.

This kind of marketing is popular with games sites that sell a sword for 5 cents or a bucket of water for one cent.

I'd love to take it further where authors could also purchase other author's products from their credits.

Any suggestions folks, or can you at least tell me where I should be looking. I tried Hotscripts with no luck.