Yes, I used .diy extension

We think the same way. Of course I can assign it myself. I will make single file installation which will register new file type when installed.
There's no need for two different fily types because everything is same but board display.
I think I mentioned export to gif/jpg/bmp before, it's not a problem. Maybe gif because it's not native supported by Delphi, but I think I can manage it. For png I'm not sure. Printing is also included.
If anyone wants to participate I would need two things (in bot 32x32 and 16x16px):
a) icon for file type
b) icon for program
if nobody wants to make some I'll use one of "regular" icons, but it would be cool to have nice icons.