  A correlation of X-ray source and Halpha emission-line object catalogues in
the Small Magellanic Cloud (SMC) shows that more than two thirds of the
optically identified Be stars in Be/X-ray binaries are found as emission-line
objects in the catalogues. On the basis of this result we propose up to 25
X-ray sources mainly from recent ROSAT catalogues as new Be/X-ray binaries and
give their likely optical counterparts. Also for the five yet unidentified
X-ray pulsars in the SMC we propose emission-line stars as counterparts. This
more than doubles the number of known high mass X-ray binary systems in this
nearby galaxy. The spatial distribution of the new candidates is similar to
that of the already identified Be/X-ray binaries with a strong concentration
along the SMC main body and some systems in the eastern wing. The new
candidates contribute mainly to the low-luminosity end of the X-ray luminosity
distribution of Be/X-ray binaries. A comparison with the luminosity
distribution in the Milky Way reveals no significant differences at the
high-luminosity end and the large number of low-luminosity systems in the SMC
suggests that many such systems may still be undetected in the Galaxy. The
overall ratio of known Be to OB supergiant X-ray binaries in the SMC is an
order of magnitude larger than in the Galaxy, however, might show spatial
variations. While in the eastern wing the ratio is comparable to that in the
Galaxy no supergiant X-ray binary is currently known in the main body of the
SMC. Possible explanations include a different star formation history over the
last ~15 My.
