In town tonight I saw a scaffold made of brackets that jack up on double 2x4's that you build and brace on site for up to 30 feet high. About $65 per unit -22 lbs plus your lumber.http://www.qualcraft.com/PUMPJACK.html#pumpjack4
I thought your idea of the easy way meant digging a hole and putting the scaffolding on the inside? ;)
I''ve actually done that-- My ceiling in the deep part goes to 16' in some places making scaffold necessary or at least a rope through your belt loop tied to a log on the ceiling ;D