A[IMG ALT=""]http://www.cakecentral.com/content/type/61/id/3320663/width/350/height/700[/IMG]

Hi there! How would I go about making this cake? Any idea what is being used as support? Thanks in advance. :)

You could just have a cube of dried gumpaste coloured black big enough to support the cake on top like here:

http://wokinghamcakes.wordpress.com/2012/04/25/monster-truck-cake-tutorial/

You could cover it in 'mud' to make it less noticeable. 

http://www.cakecentral.com/g/i/2391957/a/2392954/gravedigger-monster-truck/

I also made a grave digger monster truck cake for my little bro.  structure I employed was using two psb tubes cut at different heights and screwed into cake base, then mounted another board (size of truck base) on top.  hope that helps.  I've also used styro in the past and covered with black fondant to blend in.

good luck