As far as I know, no such mechanism exists. Elevated blood glucose levels are the only stimulus to raise insulin levels, I think. Insulin levels probably aren't useful for the body to measure since they depend on various things like carb intake and activity.
DKA occurs because the body isn't able to make enough insulin. A mechanism that senses insulin levels wouldn't help preventing DKA.
I believe this is not so much a mechanism to get rid of excess glucose, but rather the inability of the kidneys to reabsorb excess glucose from pre-urine. Getting thirsty is the natural consequence of this process. As glucose can't be excreted without water, you constantly need to compensate for the loss of water.