Hi, Gordon. Many years ago. I saw attic stairs that extended on slides rather than folding. They were kind of like an up-side down extension ladder. I have no idea who the manufacturer was or if they are still made.
But I have a question. The fold down section of the stairs is normally made long so the stairs can be cut down to accommodate various ceiling heights and even floor variations. Have you checked the math based on the actual length that you will need to fold down or on the the supplied length?