We are remodeling our 1948 home, and the previous owner was quite tall. We are trying to replace our exterior door, and have come across a wonderful deal on a door. Here is the issue: How can I make a 36w x 78L door fit into a 36w x 82L frame?
The simple answer is to fix a 4" high piece to the top of the frame where the door would go.
However, you would need this to match the thickness of the new door you are fitting and you'd need to weatherproof the gap between this and the new door. Assuming that the door opens inwards you could fit a piece of wood across the gap.
Paint the wood the same colour as the frame to de-emphasise it, or paint it a contrasting colour (the same as the door perhaps) to highlight it.