Shopping Cart Needed for Digital Downloads Site

I am in search for some type of shopping cart script.

I plan to start a new site in selling a few website scripts. There will probably only be a few products for sale.

I would like to have the customer create an account. From the customer control panel, he can download the digital product that was purchased.

Many shopping cart products are able to do what I have described so far. These are some additional features that I would need...

I would like the customer to be able to return anytime in the future and re-download the product. There is no expiration date or download count.

If there is an update or patch, I would like the customer to be able to download the patch file for the product that was purchased. This patch file should show up in the customer control panel. When I release an update, I want this update to be available for all customers that purchased the specific product.

I would like to be able to email all customers that purchased a specific product.


Does anyone have any suggestions?