I get TDK SM 60's at MARS. don't know if there is onne near you though. Tower records carries them too, but only in 30 and 15 minute versions and are much more expensive. I haven't seen Sa-X's in a while anywhere and I think the last time I did it was a 110 minute version- yep double checked got one unopened right here! can't remember where I got it from though. Tower probably.
-jhe