  Combining newly identified and previously known BL Lacs from the RASS-Green
Bank (RGB) catalog, we present a sample of 127 BL Lacs, the largest ever
derived from a single uniform survey. A Complete sample of 33 objects brighter
than O=18.0 mag is also presented. These samples are compared to other known BL
Lac samples and are generally found to exhibit properties intermediate between
those of the previously disparate classes of High and Low energy peaked BL Lacs
(HBLs and LBLs, respectively). This result is most dramatic in the distribution
of the X-ray to radio logarithmic flux ratios, where the RGB BL Lacs are shown
to peak precisely where the sharp dichotomy between the two subclasses was
previously seen. The alpha_ro vs alpha_ox diagram also shows the RGB sample
smoothly bridges the gap between the previously distinct subclasses of LBLs and
HBLs. We also find a weak, but statistically significant correlation between
the composite X-ray spectral index alpha_xox and alpha_ro. This implies that
the more LBL-like RGB BL Lacs have a secondary source of X-ray emission,
possibly from an inverse Compton component. We also present both the X-ray and
radio logN-logS distributions for which the competing HBL/LBL unification
scenarios have differing predictions. The unknown effects of the triple flux
limit inherent in the RGB Complete sample makes quantitative analysis
uncertain, but the characteristics of the RGB sample compare well both with
results obtained from previous samples and with general theoretical predictions
based on a simple Monte Carlo simulation. Our analysis indicates that the
unimodal distribution of BL Lac properties found in the RGB sample likely
reliably reflect the underlying population, while the bimodal distribution
found in earlier studies arose primarily from observational selection effects.
