I got a copy of a bios 1807 DSDT, thanks anyway.
I edited that DSDT tonight; maybe you would like to test it?
I made the same edits to a vanilla 1702 DSDT and tested with my system and it worked so hopefully it will be the same with 1807.
The ASUS update to that 1807 bios was for better memory compatibility, so not much of a difference between 1702 and 1807.
All I have installed with my 1702 DSDT are:
1. Chameleon and fakesmc which are required to boot without iBoot.
2. JMicron eSATA and SATA kexts for drives to show as internal.
3. LNX2MAC's Realtek kext for ethernet.
4. VoodooHDA kext for audio.
5. com.apple.boot.plist = 64 bit Apple Boot Screen
6. smbios.plist = MacPro 5,1 Core i5
7. TonyMac's theme.
8. OS X86 software > all 4 options.
9. System Utilities > both options.
Rename the attachment to DSDT.aml and stick it in /EXTRA.
These are two versions based on bios 1702 and 1807.
Hope it works!
Update: Added a P7P55D-E Pro DSDT bios 1502 if anyone wants to test it.