AliCommerce uses PayPal API and other 3rd party components, which need to run under Full Trust. When you choose a hosting provider for your AliCommerce store, please check this with them first.

As I type, without modification, GoDaddy and Webhost4life shared hosting DO NOT work with AliCommerce. Please avoid them.

We have some customers hosting their AliCommerce sites with WebSecureStores, so far we haven't heard any complaint. So if you're looking for an AliCommerce compatible hosting provider, please contact them to find out which plan is the best for your business needs.

If you’re hosting AliCommerce with other providers, please share your experience with community.

It depends how it's configured. Read this post: community.discountasp.net/default.aspx  

Edited: in the above link, it says 'We confirmed with Scott Guthrie that running each appPool w/ unique id with Full Trust is secure.'

You're right on that full trust is quite popular in asp.net ecommerce. Most commercial payment components need to run under full trust, even PayPal API requires it. There isn't much we can do about it.

Regarding launching a hosting service, go for it. Maybe dnn ecommerce hosting is not a bad idea?!