Looking for a section for what is basically a barn door - sliding 12’ wide pair x 30’ tall. Little bit larger than interior doors I am use to.
Russ, I usually use Richards Wilcox barn door hardware - https://rwhardware.com/product-finder/ and then specify whatever the door materials are. The hardware manufacturer should be able to help you size the hardware.
Russ, are you looking for the door section itself? Whether hollow metal or wood, I’d just use your normal door section, although for doors that size may need additional beefiness and reinforcing.
For hardware, I fully agree with Ken. Richards Wilcox has a good selection of heavy-duty door hardware. We’ve used them for gates for the panda house at the National Zoo.