Ok... I reread your post and looked at a few things and think I am starting to understand a bit more. Correct me if I am wrong (I numbered them so you can confirm or correct my statements easier).
1. Freeduino is the programming board and you programmed the chip on it before putting it in your MPGuino.
2. The MPGuino (V2.0) kit basically comes with the Freeduino/programmer and MPGuino all on one board as found here:
Fundamental Logic
3. The Iduino and Arduino boards you can buy to make the MPGuino yourself are (like the MPGuino V2.0 kit mentioned above) the programmer and MPGuino all in one.
4. If I buy an Arduino or Iduino, I would basically attach that to my custom made board and screen to make the MPGuino (so basically I would have the Arduino/Iduino, a screen/board that comes with it, and my custom MPGuino board (that I would make from the item in the parts list found in this post:
MPGuino release one workspace)
Also, is there any reason thsi screen should not work:
White on Black 16x2 5V LCD
