Desktop/SQL pos system multi users

We are a small? mobile distribution company.? We have recently added multiple trucks and have outgrown our current software.? We are looking to have a desktop application created that? is able stand alone? with the ability to syncronize data via web.? I quess it would be similiar to software that manages several warehouses.? We would need an entire POS system built.? I am able to provide a copy of our current software to qualified developers so that you are able to get a general idea of the features that we would need along with others which we could discuss.? Thank you for your time and consideration