In the Totenkopf Designer Notes there is this reference.
You will see that there is a number of 11th Panzer or Gross Deutschland units in here. The 180th Separate Tank Brigade, a Gross Deutschland unit, can be switched with a Tank Brigade and a Motorized Infantry Battalion from the 2nd Tank Corps.
31st Tank Corps can be switched for 2nd Tank Corps.
Cool. I'll sub in the 2nd Tank Corps. I just wanted to make sure I wasn't just being stupid and overlooking it.