i know there is actually a projectile called +force_push, or something to that effect...
its what either gork or pic use in the level where you fight them.
i also made a "hack" a long time ago that edited force throw and made it so you targeted yourself, then defined the "throwable object" as whatever enemies were nearby and reversed the direction of the throw so you efectively pushed enemies away from you... dont know if that is along the lines of what you are looking for?
Actually it was as simple as making it a puppetless actor. Actor templates are pushable. Throwable objects are throwable and only weapons are pullable. Thanks to Edwards inate sense of curiousity, he is pursuing the ability to merge all 3 into one via a class cog. So lets see what the wiz can whip up.