Web Hosting "Shopping Carts"

Can anyone reccomend any good web hosting shopping carts?

A script that allows users to add available domain to be registered and
their corresponding Hosting plans, to be registered/setup after payment is approved.

It seems to me tha the trickiest part is registering the domain, should I be looking
for a domain reistration shopping cart system, that can also add Hosting Packages instead?

Here is what I have found, please offer some feedback if you.

Wants:
-I would prefer a PHP based script.
-Compatible with : OpenSrs, Authorize.net and PSI Gate
-different tax rates for different countries

Thanks,

Mike

http://www.zaygo.com/products/hostingcart/
http://www.dreamcost.com/?page=shop/sol_software_dreamhost_pro
http://www.modernbill.com

i use asp, but the best one i've found for asp is :
http://www.cactushop.com

We are using a custom perl script. But, it is still in beta testing. :)