This prohibits SSH logins via password, but does not strictly enforce what commands are allowed to be run (and all options allowed) by a specific which is what I was looking for.
I found this article series from 2002 (!) quite good.
http://www.hackinglinuxexposed.com/articles/20021211.html
The last in the series
http://www.hackinglinuxexposed.com/articles/20030115.html
introduces a method (via perl script) to control which commands can be run via ssh.