I'd have some questions too. In an old video, the image was fairly "widescreen", in newer videos however, the image is 4:3 and the border is a bit off-centered. I have read now in this thread that the image is now 800x600, which I assume should be basically a PAL image (720x576) inside a slightly larger border. Will this be the final design? Will it be more centered in the end?
I think having a 4:3 image is not bad in general, as it's probably closer to the original C65 anyway (when googling for C65 pictures, the screen image in C65 mode is also 4:3 on standard Commodore monitors). But I wonder about those higher res modes which were originally planned, are they now off the list? (which I wouldn't mind since I wouldn't have used them anyway) And as said before I wonder about the centering and such.
Also, have you tested converting the VGA image to RGB or Composite or S-Video? Because I'd like to run the MEGA65 with a real CRT PAL monitor if possible, instead of a VGA monitor...