I can develop you some software that enables you manage your many computers from a single computer. The management will be able to be done just with a web browser (so a phone or tablet will also work). On the managed computers end, I will write executable programs that listen to a central server to take orders. I have done it before for another client and he got very satisfied. I will use PHP and Autohotkey. I'm very experienced about every aspect (software architecture, client-server HTTP communication, windows desktop automation with Autohotkey, making GET/POST requests with AHK, and so on). I can make changes according to your requests.