For a reliable and useful remote control solution, you're looking for an IPKVM with ATX power control. To setup the power control, you effectively set up a parallel circuit where your power switch connects to the motherboard, letting the KVM effectively press the power button 'normally'. As a bonus, you can connect to the video and data of the KVM for even more remote control options, like be able to troubleshoot boot issues or load a virtual CD/DVD to upgrade the OS.
For tinkerers, I recommend the PiKVM, either DIY or Preassembled. It's important to know that a RaspberryPi is energy efficient compared to an x86. This guy crunched the numbers
If you're looking for a product instead of a project, I'd recommend JetKVM.
