Retina 5K - AMD Boot Camp Driver failure

I would like to begin a discussion of the Boot Camp Drivers for the AMD video card in the stock Retina 5K iMac. There is a thread that demonstrates what appears to be a successful install of the drivers, and a thread that demonstrates a non-successful install.

A non-sucessful install looks like this:

The drivers tab indicates that driver version 14.200.1002.1002 is installed.

This is the stock Boot camp driver install. The latest beta Catalyst drivers from the AMD website will also return the same results.

I have had conversations with Apple support and it seems there is no official support for Boot Camp after install. They have no useful information beyond blaming Microsoft and/or AMD and acknowledging that there are threads at Apple communities that confirm people are having this issue.

For those of you with the Retina 5K, can you get the AMD Boot Camp drivers to function? If so, what did you do to make it work?

Can you list your specific hardware load out?

I am not concerned about true 5K support in Windows, that is not the issue at this point. The issue is that the AMD Boot Camp drivers will install, but Windows refuses to load them and returns a 'code 43' error.

Retina 5K - 3.5GHz i5, 8GB ram, AMD Radeon R9 M290X 2048MB