  The highest-mass stars have the lowest frequency in the stellar IMF, and they
are also the most easily observed stars. Thus, the counting statistics for OB
stars provide important tests for the fundamental nature and quantitative
parameters of the IMF. We first examine some local statistics for the stellar
upper-mass limit itself. Then, we examine the parameter space and statistics
for extremely sparse clusters that contain OB stars, in the SMC. We find that
thus far, these locally observed counting statistics are consistent with a
constant stellar upper-mass limit. The sparse OB star clusters easily fall
within the parameter space of Monte Carlo simulations of cluster populations.
If the observed objects are representative of their cluster birth masses, their
existence implies that the maximum stellar mass is largely independent of the
parent cluster mass.
