johannes point of sale with touchscreen

Point of Sale software with touch screen for retail and butcheries 1. Fully point of sale project with touch screen function 2. For the retail industry and more specifically for butcheries It must have all the functions associated with a great point of sale system and with touch screen. A critical component to the software is a "calculater" system, build into the database that can determine various variables like stock losses, shrinkage, percentage losses per carcass ect. so considerable research should go into the project to present me with 3 options of similar products and who can calculate everything re meat. So it must be a "clever" system. I will need 3 websites that you believe have that or systems that can deliver what i want. Need full source code. You need to have extensive experience in developing this type of software and need to be able to write full specs what you will do and how you will go about it. microsoft and linux ? compatible