I'm thinking about doing something like that. Instead of using a 4x4 across the top use a 2x4. Instead of having a 4x4x16 post only use 6' with 3' in the ground. Attach a 12' 2x4 to the 3 4x4 with 2-3 bolts. When it's time to harvest you can take all but one bolt out and lower the trellis where it can all be reached from the ground.
