r.cross in the version at CERL is a little different than what
was released with 4.0.
The difference is only that category labels are built from the
category labels of the input maps (rather than from the map
names).
In general, however, the vanilla 4.0 version and the current CERL
version function the same: unique combinations of values from
multiple layers are assigned unique categories in the resultant
map. This applies only to unique combinations within the current
region and masked by the current MASK. The resulting raster
values from either version will be the same, but the label files
will be different.
Michael