I have been following this thread as well for several weeks. I have a very similar problem but it varries sometimes from the others.
Here is in a nut shell what happens with my iMac mid 2010 and osx10.8.1 :
I have a iMac mid 2010 27”. After upgrade from Lion to MLion I have the following problem:
When I wake up the iMac from sleep I see a spinning beachball in the menubar when pointing the cursor to it. It only shows on the original standard Apple icons ( like:TimeMachine;Bluetooth; WiFi;Sound volume;date and time;user name and finder.)
On the other icons put there by other software (Speedtools pro;Dropbox;Intego Virus barrier) there is no spinning ball.
This happens when I put the iMac to sleep manually or via powermanagement .
When done manually I see that ,after waking up, the time/date shows the moment I put it to sleep manually and it stays so for about 10 minutes than returns to correct time/date.
This does not happen when the iMac is put to sleep via powermanagement.
Some times the Wifi is greyed out, sometimes not.
After some time, no more than 10 minutes at the most the spinning ball is gone and everything works normal.
When using the iMac during the spinning ball most of the time it works ok. But sometimes a program like safari will cause freezing. Only a hard shutdown and restart via the powerbutton will help.
When logging in with an other user account or
starting in safemode I do not have the above problems.
I have been following several threads on this issue on the Apple support and tried out all the suggestions they made there, but none of them worked for me.
Because the problem varies so much it is not possible for me to pin point the cause of it.
The only common factor is that it happens when waking up the iMac after it has been put to sleep.
I tried to sent it via the bugreporter but every time I tried to log in I get an error report.
Any help is welcome,
peterwillem