The metal cross dowel is a “knockdown” that is quite strong, I believe. A hole is bored toward the end of the rail and a metal cross dowel is inserted. There is generally a slot on top of the dowel to rotate to receive a bolt. Horizontal boring along the end of the rail has to be drilled to accept the bolt. The key that lends to great strength is a long bolt and a hole bored not too close to the end.

I am thinking about the same concept except that the dowel is wood and instead of bolts screws are used.  Just one pilot hole needs to be drilled horizontally. Again for strength the hole should not be too close to the end and the screws should  be long.

Unlike pocket holes, the screw is driven in from the outside, not along the rail. I believe this is far stronger than pocket hole. This is mostly because the length of the bolt/screw and the greater distance from the end of the wood (wood has more integrity). 

I am building stands to hold two thousand pounds.

Any opinion?