Also, Crius frames can be purchased separately, and you can build it with your choice of components. Offical Dahon and Tern frames cannot be bought individually, you will have to get the whole bike before upgrading it.
Check out this custom build using the Crius AEV20 folding bike frame! It is an aluminium frame for V brakes, and is designed for 406 sized 20 inch wheels.
Wheelset and Tires
Shifters and Brakes
Seatpost, Saddle, Pedals
Handlebar, Grips and Misc