Prepaid credit purchase and currency

Hi Everyone !

I'm looking for a module that could change the type of currency on the shop.
Basicly, I would like to use my shop as they do on :
http://us.fotolia.com/Member/BuyCreditsChooseAmount

Clients would buy xx "credits" for xx Euros and then use these credits to purchase products ...
.. The product price would be shown in credits as well.

The closest module I found so far is "Buy Store "Credit (v15x)"
http://www.opencart.com/index.php?route ... on_id=5178

... but it's quite far from what I need !

Any idea anyone ?
Cheers,

Dalken

I have this same question!

Create a product that enables users to buy reward points
Use points to purchase everything else.