As a matter of fact I have created a very cheap but complete full-featured POS (Point Of Sale) based on Android and dedicated hardware integration. This project has been done with a Chinese partner (you can see it on my website www.balearicdynamics.com) There is a key version of this product that should provide a independent web server. I think that doing this with a PI there will be the advantage that it can be fit as an add-on to the standard design of the POS device - or, better fit inside the device itself - working in a networked environment. I think that this is a very efficient way. I have approached also this kind of things with a small linux embedded for Nintendo and this solution demonstrated very efficient.
