I'll my machine controlling laptops are Referbs off of Ebay for sub $200, including the one I mentioned for my laser. I just get whatever was a solid business class Dell 6 or 7 years ago when I need a new computer. I think I could have better described it as "higher build quality" than tough. Just not a cheap shitty laptop.
I have a couple of RPi's on the 3D printers, and that is also an option. A Pi, some linux, keyboard and monitor and you're where you need to be, with a computer that can be pretty sealed up.