Does something like this exist?

Hey all,

I am doing some work for a small business and I am trying to reduce/remove the large towers they are using for their point-of-sale systems. They have a central server that their point-of-sale systems connect too.

I want to look at replacing their towers because they take up a lot of space on their counters. I was looking at barebones computers or perhaps a laptop connected to a docking station. However I had a thought and was wondering if anyone knew if something like this existed:

Is there like a mini-barebones-like computer that can connect via ethernet to a server and log-on as a specific user. Then all the input/output is communicated over the ethernet (ie. mouse/keyboard input; monitor/printer output). I was thinking of something like a really small laptop, minus the screen, that has ports for usb/monitor/ethernet, which doesn't have an os but is able to boot/connect to a central server/computer.

Thanks for any ideas!