<p>The question posed came about during a 2nd Year Comp Science lecture while discussing the impossibility of generating numbers in a deterministic computational device.</p>

<p>This was the only suggestion which didn't depend on non-commodity-class hardware.</p>

<p>Subsequently nobody would put their reputation on the line to argue definitively for or against it.  </p>

<p>Anyone care to make a stand for or against.  If so, how about a mention as to a possible implementation?</p>

Eh, I find that this kind of question leads into discussions about the meaning of 'truly random' pretty quickly.
I think that measuring pings would yield decent-quality random bits, but at an insufficient rate to be of much use (unless you were willing to do some serious DDOSing).
And I don't see that it would be any more random than measuring analogue/mechanical properties of the computer, or the behaviour of the meatbag operating it.
(edit) On a practical note, this approach opens you up to the possibility of someone on your network manipulating your 'random' number generator.