MarketPress POS system integration

I'm wondering if anyone can tell me if MarketPress or any other eCommerce option can be integrated with a Point of Sale (POS) system. I've looked around and found this thread from a little over a year ago: https://premium.wpmudev.org/forums/topic/marketpress-as-a-small-pos-system-is-my-idea-feasible

I'm wondering because I've got some friends looking for new ideas for plugins, but they don't use WPMU. If this functionality doesn't currently exist, they may be interested in making it.