With remoteable KVMs and power outlets that can be remote controlled, there is only one important missing bit until I can give up visiting machine rooms almost entirely: a remote-controllable DVD drive.

The easiest way to do this would be with a USB device that pretended to be a DVD ROM drive, but was actually a big pool of disk space with ISO images. You'd give it an Ethernet connection so you could control it remotely to 'switch' the 'discs' and so on.

(Since Linux has target mode USB drivers, I believe you could actually build this today with the right hardware and some work. You'd want a machine with a lot of USB connections so you can hook it up to as many servers at once as possible.)

Our local experiences is that modern hardware and modern operating systems are generally happy to boot and install from USB DVD drives, but your mileage may vary.

(If you are spec'ing new servers, please give them DVD drives. Unless you are buying in industrial quantities, the amount of money you'll save by doing otherwise is not worth the aggravation, and probably literally not worth the cost of the wasted staff time.)