"I think it looks pretty cool too."

If I was looking for cool, I would probably try something a little more primative like, say bind the joints with rattan, or wire as is done with the furniture or scaffolding; or, I would make the joints coped as they are with normal metal racks and build up some fiberglass tow (aircraft spruce) around them for a low impact structural joint.

"Considering most Bamboo is stronger than steel I see nothing wrong with Bamboo used as rack material."

That is misleading, though. While they say that is true, it is true on a weight not volume basis, and it is only true of the power fibers not the other 80% of the wall materials. That is why it is a little more painful trying to break 3/8" 4130 over your knee compared to the average bamboo tomato stake.

"To keep out the elements I am waiting for the bamboo to dry a bit and then I am putting on 5 coats of tung oil (is that legit for bamboo?)"

As you probably know you can significantly increase the strength of Bamboo by baking it. Tung oil, though used on boats, does water mark readily. Adding about 1/3 by volume of some kind of spar varnish helps drying, build, and will reduce/eliminate water marking.

My bamboo fenders were finished with marine epoxy, and strangely enough the results are natural looking and, of course, very waterproof. Not a good finish for high sun zones, though. You would need to topcoat the epoxy with UV varnish for that use.