"Always good to find Pentaxians around."

I plan to have a frame custom built using titanium. I have the following requirements: 1. the bike would be used for multi-modal transport, therefore, it should be as light as possible (preferably 8Kg or less). 2. The frame should be able to accommodate 700x28C tires with C-brakes as well as 26" tires with disk brakes. 3. The bike in folded configuration should be able to fit in a small car trunk and be carried into MRT and high speed trains.
The movable joint between down tube and BB shell exists long before Changebike. Their invention is the notched joint between the top tube and the seat tube. I do not need that. I would cut the seat tube and install two cramps, using seat post as the connecting tube.