I (and my colleagues at work) remotely manage a lot of servers in many data centers worldwide. We use a serial terminal server (cyclades) which allows for SSH connectivity (then over serial) to any machine configured and plugged into the serial port. this allows us to reboot the machine and remain connected to it for bios changes, OS rebuilds, single user mode, etc... we also use power columns that have remote control options like powering off a specific outlet so we can do cold boots. finally, we have a Perle serial device on a separate IP block in case we lose the data center's router or other non-all-encompassing problem upstream from us. seems like the serial terminal server would do what you want. it is a separate device that needs it's own IP but otherwise will allow you to control the machine from power-on to boot-up so you could configure linux anyway you like. it's not end-to-end encryption although SSH is encrypted and you can configure the cyclades device to use it exclusively. but now it seems you don't really own any of the hardware and therefore you are not truly colo and therefore can't walk into the datacenter with new equipment and set it up yourself. the problem here is that you don't own the hardware, so you don't have much leverage in the situation. you need to physically own the hardware in your future hosting plans. good luck dude.