Any ideas how the top tier is created? Color Im guessing with an airbrush machine (which I have) How about the roof?[postimage id="3448" thumb="900"]

You can use an airbrush or you can use some vodka and brown gel color.  You can use a clay extruder for the roof.

The way I see it one would wrap a small round cake w/a tan colored fondant; score the 'logs' w/a kabob stick or similar, then airbrush.  Using brown, thinned down w/vodka would work but you would need to have a *very* little brown or it will end up a very dark color.  I agree w/using an extruder gun to make the 'strings' for the roof.  If you don't have one try pushing very thinned down fondant through a 'grass tip' OR cut very tiny/thin strings of fondant w/a knife.