Having a small issue with a judge who will not find the extreme intoxication enhancement in pleas. He will accept the plea but refuse to find the enhancement as true and thus reduces the charge to class B DWI. Is there anything to be done besides invoke the state's right to trial? Can he do this?

This sounds familiar. Check out In re State, No. 08-12-00165-CR, 2013 WL 634581 (Tex.App.--El Paso, Feb. 20, 2013)(orig. proceeding)(not designated for publication). If the enhancement is part of the plea deal, the same logic should apply. Good luck.

Here's an even more recent opinion out of the Austin COA from this January, State v. Villareal.

The bottom line is that a judge cannot modify a plea. They can wholesale accept it, or wholesale reject it. In this case, they found a way to get mandamus relief.