The tripod top (fig5) is a single layer of ¾” oak plywood 8” in diameter. 
The blocks that hold the tripod legs are 2 layers thick with a ¼” grove cut with the router in one and then the 2 glued together.  I had a difficult job trying to drill a hole straight through the blocks even with a drill press.  ¼” threaded rod runs through the crutch leg and the block with self-locking nuts on the ends.  A short piece of wood dowel was epoxied in the end of each cut off crutch top to keep it from collapsing.  Existing holes in the crutches were utilized whenever possible.

The cost of the whole thing was under 25 bucks.  Hardwood plywood is not real cheap.  If one could not scrounge up the pieces ordinary plywood may be a better choice.  If you have a whole day to yourself you could build it. 
The longest period of time that I had was about an hour and a half.  So it took me about 2 weeks of spare time to complete once I had decided how to go about it and had made up for a couple of mistakes.
In the end the tripod is very stable and stiff.  It can support far in excess of its own weight as shown in the last image (fig8).  Is your commercial tripod rated for as much?