[rickbo_99]

While the tubular pieces are interesting, I would be concerned with the amount of machining that they entail. In order to consider them as a KOP option, I would think they would need to be molded plastic (which could reduce the weight even further without impacting the strength). I think the real merit of the design is the modular bearing block with a-centric holes. Even a tubular frame made of 1" square tubing could utilize these bearing blocks effectively for all the same reasons that you quoted.

However, as you stated in your earlier posts, the preference is to have dead axles for all but the inner driven set. These would not need bearing blocks as they are dead axles. Using a shoulder bolt for supporting a dead axle is really all that is needed so maybe these a-centric mounts would come in various options:
1) True bearing blocks for driven axles
2) 1/4-20 clearance hole for the threads of a shoulder bolt
3) 1/2" clearance hole for shaft of the shoulder bolt

Just some ideas if you really want to take this to the next level.