Raspberry pi is my favorite little single board computer. Regular variants about the size of a
deck of cards and in the 35 buck range for the Motherboard. for the W variant it's about the size of two packs of gum, and 15 buck range or less for the motherboard.. but will run full linux based OS and Open Lighting and QLC+ are two projects that will run on it. Would likely need to have a
programmer to customize to what you want, but the hardware including available touch screens, buttons,
etc is dirt cheap. I run my Theater's comm
system on a mix of pi's and cast off thin clients. Have for years and they are rock solid little machines.