Passthrough means the shareholders will be taxed on the income that the corp is not being taxed on. Unless this money is actually distributed to the shareholders I don't see it as being too popular. In addition the income would be taxed as ordinary income to the shareholder, instead of favorable rates that divs are taxed at.

Obviously I am not familiar with the vehicle you are describing. However from your description I can tell you it's not as cut and dried "a great deal" as you are describing. Otherwise, bottom line, everyone would be doing it.