yeah "very close" is not the words I would use thanks though, I have been checking craigs every day and found some good ones, but they were either sold already, or just didn't respond (probably sold). I'll keep looking.
Check the serial number to determine the year --- if a U.S. model, the first letter is always D, denoting Dahon. The second number is the year of manufacture. The next two numbers are the month of manufacture.
For example, a serial number D302....... would mean a bike produced in 2003, month of February (02). Then a letter T followed by 4 numbers which is the actual number pertaining to the bicycle frame produced that month.
(copied from a posting in the Dahon forum)
Using the prices at www.thorusa.com as a guide, looks like a standard seatpost is $37 (but there are some other, higher-priced options), a seatpost clamp is $17.50, and a saddle similar to the original is $19. Based on the color, if it is a U.S. model, it is a 2007. See: http://www.dahon.com/archive/2007/us/speedd7.htm