Magento is nice, you need to learn how to skin it but it's fast once you get the hang of it. You can make a nice looking shop with it. They have a free and paid version and an optional mobile setup. You can also do mass csv importing and they have a ton of free and paid modules. You can find anything from blogs to custom delivery and affiliate systems.
Heres an example of a magento shop:
http://cms.template-help.com/magento_32228/
Here's one, lot of broken links but it's an example of how nice it can look.
http://web-experiment.info/sextoys.html
The downside is for the free version, you obviously wont get much support, but if you or your tech guy knows his/her way around google, you can find most anything you need. Their official support is like 1k an hr though lol but I havent had any issues I haven't been able to find an answer to.
Heres an example, I just googles paxum and magento and found a tutorial on how to build your own payment modules.
http://www.magentocommerce.com/wiki/...-method-module
I didn't get the impression you needed a cart, but since there are carts being thrown out maybe this will be useful to someone reading this post.
Nice read btw, thanks.