Seems this was missing. Booting into Recovery should help, and if only to effectively repair the internal HDD, if that's the cause for your trouble.
You should also check the Console app for crash or even kernel panic reports from when your Mac stalls. Copy & post the relevant lines here.
I am quite certain it isn't planned obsolesence. I am writing on my mid-2009 MBP, which works perfectly under 10.8 - including wake from hibernation.
My suggestion is that you do a clean install of 10.8.2 (i.e. erase your hard disk, install the OS, and then migrate your user account, apps and data from a backup). edit - it doesn't take so long - only about 2 hours from go to whoa, and it doesn't need supervision the whole time.
It is apparant that you have spent enough time mucking around with items that haven't addressed the underlying issue. Do you need instructions for this?
...do a clean install of 10.8.2 (i.e. erase your hard disk, install the OS, and then migrate your user account, apps and data from a backup).
If... IF it's not caused by something within the user account - which would then be brought back onto the new "clean" system...
A truly clean install means wiping the disk, re-installing OS, manually installing all apps fresh and from scratch, and manually migrating only user data (as in document files) but nothing from the user library.
Well, a fresh install seem's like the only way to resolve this. But I agree, that I shouldn't be transfering to much from my library. But format c: ist something that will take a lot more than 2 hours.
Just for the record: I also did the fsck -fy in Single-User-Mode and tried booting into Safe-Mode with the test-admin-account (deleted sleepimage from there as well) but the issue remains.
Here are some log entries that might be helpfull too:
This is from the system.log and I believe there might be a problem with the login window (that's what should come next when the machine wakes):
loginwindow: *** WARNING: -[NSImage compositeToPoint:operation:fraction:] is deprecated in MacOSX 10.8 and later. Please use -[NSImage drawAtPoint:fromRect:operation:fraction:] instead.
loginwindow: *** WARNING: -[NSImage compositeToPoint:fromRect:operation:fraction:] is deprecated in MacOSX 10.8 and later. Please use -[NSImage drawAtPoint:fromRect:operation:fraction:] instead.
This one is from the Powermanagment Log:
FilteredFailure Sleep - Filtered Sleep Failure Report - Power Button Shutdown - Platform Failure (Fail code:0x1f006700)
For now, I'm going to use my machine back in hibernatemode 3 and just not let the battery run down to much...
I just wanted to tell how you my solution.
I did a reinstall with the latest ML Installer. I just ran the Installer with my OSX running. I only had my TM-Backup made before that - then removed all deviced from the machine and let the installer do it's thing.
When I came back to the machine a rough two hours later, I had the login prompt with my user accounts and data still in place.
Loging in and finding most of my stuff unchanged. (Printers are gone, as far as I can see it from now.)
But Hibernation is working again!
A small note to that: My mac does not promt for a password, when waking from hibernation. Just a small security issue - maybe it will be different with some time elapsed. (I was waking the mac right after hibernation had started.) I'll check that out later. For now, I'm happy that I don't have to switch of the machine hard and kick the file system out...
Thank you guys for the help!