Why network booting is not a good answer
It might seem that the obvious answer to my desire for remote controllable DVD drives is to netboot my machines. Unfortunately it's not a good answer.
Booting a machine is only a tiny sliver of the problem; the real problem is (re)installing and testing machines. While a lot of operating systems have some sort of a network install system, there are three core problems with netinstall setups: they are almost always second class citizens (partly because they are usually used much less), they take extra work to set up, and they make the netinstall server a crucial core part of your disaster recovery environment and an exception, since it is not installed the same way you install almost everything else.
It need not be a big disaster to cause problems; all you need is to lose both the netinstall server and another server. At that point, either you have to put the other server back together not following your usual build procedures, or you have to get the netinstall server rebuilt first. (You can keep a backup netinstall server, but then you have to make sure that the primary and the backup don't drift out of sync.)
If you have lots of machines in a uniform enough environment, sure, netinstall setups are completely worth it. But otherwise, network installs are nowhere near the level where it's easier to use them for some random new machine and operating system release than to swap a few CDs or DVD.