Looks like this thread brings many of these "missing" cases full circle. Origionally, here on websleuths, they were all listed under the topic area of Cold Cases. About two years ago, they were put in the present format of "Missing in the (decade)".
I have always felt that some of the missing cases and unidentified body cases might be solved by examining similar unsolved cases with known victims and suspects.
The Cold Case section is still here on Websleuths, but not in the same section as the Missing cases.