i have no idea where the 7900GTs have gone where you are
in australia there is still a good supply of them. the 7900GS is basically a GT gpu with 4 pipelines locked. it's almost like a new and improved version of the 7800GT.
edit: awesome!!! i found out the stock fan was only running at 30% speed in 3D mode so i used RivaTuner to put it to 100%. i'm about to bench at 600/800 which already seems relatively stable now
. stock fan and no volt mods, yay!!!
edit2: yeah it does seem fairly stable at 600/800. i 3dmarked and got 5089 on 06. i'm about to 3dmark again with an overclock on my processor and see what i get.