Dear sir/madam,
we are specialized in online stores development, based on the opencart platform, which supports much more than you described.
We have experience both will small and big stores, with multiple payment gateways, various product ranges. We also develop opencart modules, plugins and addons, so if you need something special we can provide it.
The visual design can be customized to anything that you need.
If you want to see some of our past work please let me know.