I had to look hard, but I remembered reading this and thought it was interesting, so I spent the time to find it again after reading this thread.
It's copied from audioholics dot com/editorials/making-the-perfect-honey-mead
Icing
If you care to make a higher alcohol, higher perceived sweetness, higher bodied Mead, it's possible to take portion of the Mead (don't recommend doing the entire 5-gallons), and placing it into a separate container with a wide open top, such as a clean 2.5 Gallon Bucket. Take this solution and place it in a freezer overnight. In the morning, you will find an ice block floating on the top of the bucket. Remove this block as carefully as you can. It will likely be slushy and break up as you remove it. What you have left is about 40% to 60% of what you started with, which will consist of a concentrated Mead. Take the ice block and toss it aside. If you are so bold, taste some of what was removed as ice. You will notice that it is not only water that was taken from this Mead, but instead, icing the Mead also acted as a cold filter, thus removing a variety of unpleasant tastes from the Mead.
You can do two things with this concentrated Mead. One is to re-dilute it back to its original gravity (or close) and notice how much cleaner it is then the Mead it started from before icing. Another suggestion is to bottle this concentrated Mead in small 6 or 7 oz bottles and use if as a liquor. If you decide to leave it concentrated, I recommend placing it in a brandy snifter type glass and slowly sipping instead of drinking. Mark my words, you will learn to love this type of Mead.