Kirk,
I duplicated the issue and I was able to install Windows 8, with Legacy disable and UEFI enable.
This is the system configuration I used:
Motherboard DB75EN AA# G39650-400
Processor: I7-3770K
Memory: 8 gb Kingston 1600 Mhz
Intel SSD X25V
Windows 8 64-bit
1. Installation: BIOS version 0041
I changed the settings on BIOS before the Windows installation to Legacy and UEFI enable.
I was able to boot to Windows with the following settings: Legacy and UEFI enable/ Legacy enable and UEFI disable.
If I disable Legacy, but leave UEFI enable I could not boot to Windows.
2. Installation: BIOS version 0041
I changed the settings on BIOS before the Windows installation to Legacy disable and UEFI enable.
I was able to boot to Windows with the following settings: Legacy disable and UEFI enable / Both enable.
If I enable Legacy, but disable UEFI I could not boot to Windows
Updated the BIOS to version 0044, I changed the settings on BIOS to Legacy disable and UEFI enable and installed Windows 8.
I was able to boot to Windows with the following settings: Legacy disable and UEFI enable / Both enable.
If I enable Legacy, but disable UEFI I could not boot to Windows
3. I did the same thing after updating the BIOS to version 0045. Same settings. Same behavior.
At this point, since I was able to installed Windows 8 with those settings previously changed on the BIOS, please try again and change the settings before installing the operating systems.
Please let me know.