I am not sure if you can get the 10mm tracking in the plastic sliding variety, For the thicker, heavier glass you usually have to go with the metal ball bearing enabled styles, Google it, as there is a couple of brands available (but more then likely you will have to buy it through a glazier)
a couple of my mates have the 10mm which they got from bunnings a while back they just cant find it anymore.thanks for the ball bearing idea i will check it out.
a massive 3 banker ,each encloser is 4ftx3ftx3ft .i got given the glass which is cut to size and would have cost a fortune so im pretty keen to use it, just waiting on the track. thanks again everyone