Well, there are rumors that Glock may soon be releasing a true .22 caliber version of some of their pistols...
I'm a big fan of my Advantage Arms conversion kit - it fits the same holsters, uses regular sized magazines instead of diminutive .22 caliber sticks and works pretty well. If you search this blog you'll find volumes that I've written about it.
Additionally, as of now (12/2009), there are no pictures of the new adjustable-grip Glocks that are rumored to hit stores in 2010...