Find panel in unusual size?

[StoffeGbg]

Hello
I wonder if anyone knows where to get hold of panel boards in odd sizes?
I need to replace some boards on the front door of the summer house but can't find the right dimensions online…
I guess it's some old standard, 9x65 is what I get it to.
/Kristofer

 

[Bläcktudan]

We usually install tracked pine plywood when customers want their old paneled doors renovated.