I just noticed your posting about ultra low flush toilets. I have the Caroma dual flush toilet and I am very happy with it. It is virtually clog proof with it's full 4 inch trap. It is also an elegant looking toilet that flushes flawlessly everytime. The following may help you know more about the Caroma dual flush toilets: Information Video clip
The Caroma toilets are available from Terry Love. Maybe you local bathroom supplier has them.