Protector for camera lens window on HTC Desire Z? (protect from scratches) Given that this phone provides no protection against scratches on the window for the camera lens, unlike for example, the Nokia N82 (great cameraphone which I also own), are there any adhesive transparent protectors that can be placed over this window but which would not affect image quality?

I've bought the screen and body protector from zagg.com by recommendation and am pleased with that but this offers no protector for the camera itself. (see: https://android.stackexchange.com/questions/2935/best-screen-protector-htc-desire-z )

I would think that protecting the camera lens window on this phone (and many others) would be more of a priority as this is actually functionality of the phone that needs to be protected - i.e. clear photos and video, rather than cosmetic - which most screen protectors do a good job of but fall short on the camera protection, it seems.
I can understand your concern, but I've also never seen a film that specifically covers the camera lens window. I haven't used a Zagg, but other screen films I've purchased in the past included the excess film on the card - if the Zagg included this you could possibly cut your own square or circle to cover the lens window. Otherwise I'd suggest checking your retailer of choice for another inexpensive film that you can use to cut your own window from.

In the past I've purchased screen protectors on clearance from places like Staples, Walmart, etc for obsolete devices so I could cut them to protect camera screens, etc.