  Recent X-ray observations reveal an increasing number of X-ray sources in
nearby galaxies exceeding luminosities of L_x > 2 10^39 erg/s. Assuming
isotropic emission, the Eddington limit suggests a population of
intermediate-mass black holes of M_bh >> 10 M_sun. However, Markoff, Falcke, &
Fender (2001) proposed that jets may be contributing to the X-ray emission from
X-ray binaries (XRBs), implying that some X-ray sources may be relativistically
beamed. This could reduce the required black hole masses to standard values. To
test this hypothesis, we investigate a simple X-ray population synthesis model
for X-ray point sources in galaxies with relativistic beaming and compare it
with an isotropic emission model. The model is used to explain a combined data
set of X-ray point sources in nearby galaxies. We show that the current
distributions are consistent with black hole masses M_bh <=10 M_sun and bulk
Lorentz factors for jets in microquasars of gamma_j ~ 5. Alternatively,
intermediate mass black holes up to 1000 M_sun are required which are
distributed in a powerlaw with roughly dN/dM ~ M^-2.
