Say_what wrote:
I currently have a detached garage with two-garage door. I was
wondering what it would take to convert from a two-door system to a
single larger door. Has anyone ever attempted that? Just wonder
what
it would entail.

Depending upon the span of the opening it will simply entail removing
the center post and installing an adequate lintel that would be
approved by your local building officials. Then installing the
appropriate door.

Rich
http://www.garage-door-hardware.com