Hi Coenraad
We are SmartjSP team, we have been working with POS solutions integreated with adempiere (using activeMQ), with idempiere (rabbitMQ) for a while.. First releases of our SmartPOS until 2.1 were based in OBPOS (client-server),but based in our customer requirements we change to a complete new architecture (100% web + OSGI) and already integrated with Idempiere to maximize the ERP features used within the POS for pricing, discounts,promotions and so on.
We already support multiple organization (branches with their own products, price list, and so on) out of the box.. Though we have been focussed within the pharmacy industry in the last year but we also support most of the restaurant use cases .... and we have tested our ordering windows on touch screen devices (7" tablets or greater) with good results ...
Hope we can help you with future projects, tou can contact us using our web portal .
Regards
Pedro Rozo.