Thank you for your question. We don't have ceiling mounted bypass hardware for this type of product.

Tell me what you have in wall mount double rods for 4 doors to cover a 9' opening with an area of 6' for the stacking of the doors.

You can go ahead and place two orders for the item in the following link. That is the 8' double door hardware. We will give you a connector so that you will be able to put up the 16' hardware with 4 doors. Thanks!
[https://www.houzz.com/products/wheel-design-double-stainless-steel-sliding-barn-door-hardware-10-prvw-vr~81205886?lid=63583335[(https://www.houzz.com/products/wheel-design-double-stainless-steel-sliding-barn-door-hardware-10-prvw-vr~81205886?lid=63583335)

I understand but it looks like there is only one 8' rod with this set. Why not order 2 -- 16' sets? Anne Reece

I am planning to buy the wheel design barn door hardware 10' long for two doors.

It says that I need a minimum of 12" above the opening, I have only 10". is it possible to have the dimensions of the actual piece of hardware, from the top of the wheel to the bottom of the hardware?