Invention: Outback grass fire blanket

Update 31st August 2010: Research results so far into fireproof tire coverings and under chassis heat protection have been a bit depressing, but I am not giving up hope... since I wrote this a few fire-ees have approached me for help with their own inventions and I am bringing their experience to bare on the problem. I also at this stage would like to formally confirm that the results of these tests and any invention that comes out of it will be made available in the public domain to ensure that the technology is provided as cheaply and widely as possible if we are successful.

This idea has been on the cards for some time after seeing the bushfires in southern Australia last year. One of the easiest things to do to stop a bush fire spreading is to attack it before it gets into the trees.
This concept involves a protective blanket that protects the underside of a tractor and a trailing blanket of fire resistant material that is 30 feet wide and up to 100 feet long that gets dragged behind the tractor as it drives along the fire line that often occurs as a bush fire burns across an open field or across a lawn surrounding a residence.
The idea is that the blanket starves the fire of oxygen for long enough to stop it from reigniting after the blanket passes.
The next step is to run this past the local fir-eys to see if it has legs.