It's likely bad taste to answer your own question, however, here I am only pointing out the argument of another in the literature. I also won't accept this answer to allow others to respond.
Surprisingly, my above guess that perfect copying is only limited by the probability of spontaneous emission... might actually be correct.
Quoting from [<PERSON>, P. W., <PERSON>, M. L. Photons cannot always be replicated. Physics Letters 92(A) no. 7, pp. 682
321 - 322 (1982).]:
"The probability of spontaneous $(n_s = 0)$ generation of signal photons is equal to the probability of stimulated generation when there is initially one signal photon already present."
"This result is traditionally expressed in the context of ordinary stimulated emission by an initially excited atom. The point here is that this fundamental law applies to all stimulated processes. Whenever there is a possibility of stimulated generation of photons, there is also the possibility of spontaneous generation. And when there is initially one signal photon, the rate of spontaneous generation is precisely equal to the rate of stimulated generation. (More generally, the rates are equal when the expectation value of the signal-mode photon number is unity.) Of course, the absolute rates are different for different purposes..."
"...It should be mentioned that Wooters and Zurek [7] have independently reached a similar conclusion, that no device is able to clone with certainty photons in an arbitrary state of polarization. Their agreement is general: The linearity of quantum mechanics forbids the existence of such a device. The argument of Wooters and <PERSON> does not rule out the amplification of any given state by a device designed specifically for that state, but it does rule out the existence of a device capable of amplifying an arbitrary state. However, if one designs a device to amplify a specific state then he is assuming a priori knowledge of the state."
Said differently: the ability to achieve stimulated emission without spontaneous emission, or more generally, the existence of quantum amplifiers capable of operating below a critical noise threshold, would mean the absurdity of allowing for superluminal information transfer via a FLASH-like mechanism: http://link.springer.com/article/10.1007%2FBF00729622.
I suppose this quote also have relevance to another question on this site: http://physics.stackexchange.com/questions/74550/why-doesnt-the-no-cloning-theorem-make-lasers-impossible
Specifically, we can say that any gain medium in the optical cavity of a laser will have some probability of spontaneous emission, and thus, rigging the gain medium so that the properties (or subset thereof) of this spontaneously emitted photon match that of the photon one is attempting to clone, means knowing a priori knowing the photons state vector. Therefore, "no cloning" does not preclude the existence of lasers or require that stimulated emission have some degree of "sloppiness". 682