My favorite iPAQ cases are the ones by Covertec. Unfortunately, being a European company, it always takes a little time for their products to make their way across the Atlantic. Today, I was looking at their web site and noticed that cases for the rz1700, rx3000, hx4700 and h6300 families are now available in North America.
Unfortunately, no cases for the newer hx2000 family are available yet (North America or elsewhere).