Develop a stand alone self-hosted eCommerce platform for www.BasicsPlus.com

In order to go live quickly, we used one of the many hosted e-commerce platform that gives you all the infrastructure to form an online shop, GoEcart.com.

Since it's a "box", we have many limitations on what we can do there.
So it's good for a starter, but not for the longer run.

Now we're looking to replace it with either a better "box" (Zoovy, Infopia) or by developing something similar based on an open source like Magento, osCommerce, Avactis or something similar.

If:
1. You are familiar with either those open sources OR you have another one that you have worked with before and you recommend
2. You have a proven experience developing an eCommerce platforms for the US market
3. You are capable of setting up such a platform in a matter of 1-2 months

Then you may be the right person / company for us...

The idea is to have at least everything we got at GoEcart today (see the list of features here: http://www.goecart.com/sb/shopping_cart_software_price.aspx (We have the "professional edition" )

And, of course, the flexibility to add/ change afterwards.

Those packages have gazillions of add-ons that can be downloaded for free or for minimal (up to a premium, in some cases) price.
We need to know that we are not loosing functionality and that either by using the built-in feature set or by incorporating a 3rd party add-on, we can have all the functionality.

We also need the capability to integrate with a POS system (for daily inventory/order updates) like QuickBooks and such. This we can discuss later on.

Please do not contact us if you don't have proven experience in such platforms.