@hannesgrebin, below are some scripts to assign one random color value to selected objects. One script for object wireframe color and one for material color. Note that the material color script also assigns a material name, to get rid of this look at the annotatons in the script.
RandomObjectColor.py (557 Bytes)
RandomMaterialColor.py (912 Bytes)
To select objects with the same material color(s) as the selected object(s), you might try this:
SelectMaterialColor.py (874 Bytes)
c.