Hello,
i'm satisfied with the Java, i bought the frame only and built it up for my purposes, it's light and stiff.
With long shaft i mean the upper tube of the fork, which is 110 or 120mm long on Dahon Bikes. There are forks available with 400mm or more. In between the headset and the (then normal A-Head-) stem is a long Carbon spacer. You lose the folding stem and it's weight.
I would keep the cassette & derailleur cause it's too expensive for the saved grams. You might check how long the cables really have to be and shorten, they look very long.