If you want 7.50x16 for 100% off road use at a cheap price, try Custom Xtra Grips. They're made by several manufacturers (Rhoden, Goodyear, Olympic to name a few), used mainly by Conservation Forests & Land in Vic and on some military Land Rovers.
"Never pay retail for tyres" is what a tyre guy once told me. When I shopped for these tyres, prices varied from $140 - $200ea. They have excellent self cleaning properties and will claw themselves out of most ruts.
The link below has a pic of the tyres. I tried googling them and found it hard to find this time around. Last time I checked (when I was buying) there were a few local links. I don't know if this means they may not be available locally. When I ordered mine, they had to order them in, but that only took a couple of days.
Highly recommended tyre.
http://www.garbee.net/~cabell/photos5.htm
