I don't think such an animal exists. There is currently not an API either, but frankly we prefer to keep our voipo panel separated from our billing system... it provides an extra layer of fraud protection.

So you'll have to develop your own strategy for building a site, shopping cart, payment gateway, billing system, support ticket system, etc.

Our company started by using PayPal Subscription buttons. That worked fine until we could develop something better.

If you do it that way, you can start with pretty much any website template, and just drop in your PayPal buttons.