Something else I would like to do is set the background color within the box itself (not the overall background around the box which I want transparent no matter what) to the same color as the textboxes are when they have focus when focus is on the checkbox control.  That way, when the user tabs through controls they can tell when they are on the checkbox just like with the other controls.

I can do that, and I tried, but it doesn't make the background transparent.