10.6.5 and Magic Trackpad = FAIL

Question

I thought I had worked out the problems with my Magic Trackpad and 10.6.5, but right now it looks as though 10.6.5 broke my Magic Trackpad's functionality.
After the 10.6.5 update, my Magic Trackpad is no longer recognized. I've reinstalled the Magic Trackpad Update 1.0 and also reinstalled the 10.6.5 combo, but I can't get my iMac to recognize the Magic Trackpad. I've also trashed the com.apple.bluetooth.plist as was mentioned in another thread, but that change didn't stick after a reboot.
Symptoms: When I go into the Trackpad Preference pane, I turn on my Magic Trackpad and begin the Bluetooth search. The dialog comes up with 'Found "Apple Wireless Trackpad"', but when I hit Connect, I eventually get an error - "The pairing attempt was unsuccessful". The strange thing is that if I go into the Bluetooth Preference pane, the "Apple Wireless Trackpad" shows up defined and connected. If I delete the "Apple Wireless Trackpad" pairing under the Bluetooth pane, then add the MT back in, the pairing works correctly. But as soon as I enter the Trackpad pane, all the problems start.
I've rebooted into Safe mod and tried the Trackpad Preference pane, but it still doesn't work there. I called Apple Support, and they advised me to do an archive/install of 10.6.0 from my SL DVD, then apply the 10.6.4 combo and MT 1.0 update, then try the MT out. If it works, then apply the 10.6.5 combo and try again. But this seems like a long process for something that I know worked up until the 10.6.5 release.
Does anyone have any other suggestions as to what I can try (other than reverting to 10.6.4)? I really want to keep 10.6.5 for the graphics improvements (I play Steam), so I can live without the MT until it's fixed. But I really want my MT to work.
Thanks.

Answer 1

I had exactly the same problem on 10.6.4, and now it still exists on 10.6.5. I am able to get my Magic Trackpad working again simply by shutting down and restarting under 10.6.5, but then it stops working if I leave my computer alone overnight or while at work.
I long ago removed all USB Overdrive components, but the problem persists.
As a side effect, I notice that iTunes stops recognizing my iPhone 4 with latest iOS when the Magic Trackpad stops working. When I get the Magic Trackpad working again, iTunes again recognizes the iPhone. The iPhone is connected via the USB cable, and BlueTooth is turned OFF on the iPhone. This suggests a possible USB issue, in addition to the obvious possible BlueTooth issue.
Under 10.6.4, I sometimes had to shut down and reboot several times, and remove all user and local preference panes, before the Magic Trackpad would start working again. Sometimes I noticed that the BlueTooth preference pane had disappeared from System Preferences, which it is supposed to do when it detects no pairable BlueTooth devices nearby. Replacing the Magic Trackpad's batteries, turning it off and on, etc., make no difference.
I suspect a software conflict somewhere, but despite considerable exploration I have found nothing. Monday, I'm going to ask Apple to replace my Magic Trackpad (because, really, I can't live without it).