I've seen a few broken auto (non -vw) flex-plates, and they always cracked out around the inner diameter.   It appears to be due to the 'flex'ing.....

 Mike B. 
  ----- Original Message ----- 
  From: Zoltan 
  To: vanagon@GERRY.VANAGON.COM 
  Sent: Friday, April 02, 2010 7:26 PM
  Subject: flex plate break

  First time I came across a flex plate breaking on me.  Any of you seen it before?  I did not take it out yet, so I'm not sure what broke there.  I only know that the three bolts on the torque converter are still on.  Now, I think either the five big bolts broke on the crankshaft or the rivets that hold the plate to the middle.  Is that some kind of safety feature in case of sudden stress?
  Zoltan