Progress to report in my quest for 3 displays in Snow Leopard on my UD3P. I now have an install with said displays, plus sound. So video working, network working w/bonjour via the fix, sound working, sleep ???. Also I do have one slight problem I've yet to figure out. If I need to restart, I have to shutdown and then restart the computer as I get the dreaded "You need to restart" error message if I just use restart. Once I figure that one out I will be a happy camper.
Update: I removed kext from the /E/E folder one at a time in an effort to find out what was causing the restart problem and removed all except the PlatformUUID.kext. Without it the clock just spins and spins and doesn't go anywhere. Then I removed the smbios.plist from the /Extra folder and it still booted with 3 displays and sound. But when I removed the com.apple.Boot.plist, I lost my 3rd display and sound. But I no longer had the restart problem. Here is a copy of the file, how can such a small thing as this be why my system acts the way it does?
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://
www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Kernel</key>
<string>mach_kernel</string>
<key>Kernel Flags</key>
<string>-arch=i386 -x32</string>
<key>SMBIOSdefaults</key>
<string>No</string>
<key>Rescan</key>
<string>Yes</string>
<key>Instant Menu</key>
<string>Yes</string>
<key>Legacy Logo</key>
<string>Yes</string>
</dict>
</plist>