I know that this sounds horrible, but...
The garage I used to work for would suggest to people who asked how
to fix the rear defogger...
"Smash the rear window, Tell insurance that it was vandalism, let insurance
replace the window."

Better yet, Remove the window yourself, tell insurance it was smashed,
etc...  Then you've got a spare when it does get vandalized.

Cheers

<sstones@io.org>
SStones             Toronto,  Ontario.