I ran an odroids ( https://www.hardkernel.com/ ) as my home server some years back. It worked nicely for what it was, but in the end the lack of good storage options (I ended up attaching USB harddrives) was what doomed it. For what it's worth, a RasPi is exactly what you're describing, minus the screen/keyboard (but with much better cooling, which is what would be the bottleneck otherwise).