A stats professor of mine back in 1990, when I was in college, worked on Tankbreaker and she still referred to it as Tankbreaker back then.
There was a sort of "baby Tankbreaker" missile that the Army and USMC evaluated and eventually bought in LRIP amounts, but the Army decided they didn't want it, and the USMC decided that they didn't want a PGM and kept the basic launcher but downgraded it from APHE to HE for use against static or very soft targets. I don't know if they kept the guidance system. Here's a YT video of it in use:
http://www.youtube.com/watch?v=pAZT_KycDpc
and here's a little wackypedia info about it:
http://en.wikipedia.org/wiki/FGM-172_SRAW
It seems like to me it would've filled a niche between the Javelin and AT4 so I'm not sure why they wouldn't have gone that way. Then the AT weapons would've gone - Maverick, Hellfire, TOW, Javelin, Predator, AT4.
Eh.