DIY carriage garage doors

I was thinking of eventually installing real carriage doors on my garage (not painting/adding veneers to the existing overhead door). My garage is too small for a car anyway, and it would offer me greater flexibility in adding a garage attic if I could just do away with the overhead door altogether.

I've looked up information on garage carriage doors, and all I can find is how to add veneer to an overhead door, or at the opposite end of the spectrum, where to buy extremely expensive custom-built hardwood carriage doors.

So what I want to know is, how hard can it possibly be to rip out an overhead door and build a swinging double door in its stead? It seems anyone capable of building a garden gate could do this, but it doesn't seem that anyone HAS done this and written about it. I grew up in a house with a detached garage with swinging doors that were just made out of dimensional pine. Anybody got plans? Should I look at barn doors, perchance?