If you want to spend $100 on a solution, Data Rescue is the tool you want to use.

If you have another OS X Mac and a Firewire cable around, you can use this method:

• Shut down the Mac with the files you want to recover. We'll call this one "Recovery Mac."
  
• Connect Recovery Mac to the other Mac with a Firewire cable and mount the Recovery Mac in Target Disk mode by holding the "T" key on the keyboard while restarting it. You'll see what looks like a screensaver with the Firewire symbol when Target Disk mode has been activated on Recovery Mac.
  
• Use the Finder to search for the folder .Trash (Note the period before the folder name.) on the Recovery Mac volume from the other Mac.
  
• Double-click on the .Trash folder on Recovery Mac (one should appear for both machines). This will open a new window with your deleted files in it, if they are still available to recover.
  
• Drag the files you want to recover to some location on the other Mac where you can find them, just in case. This will make a copy on the other Mac
  
• Now Drag those same files from .Trash directly back to where they should have been and cross your fingers.
  
• Eject the Recovery Mac volume from the other Mac, unplug the Firewire cable from both Macs and restart Recovery Mac.
  
• You should find your missing files back in their previous, pre-Trash location. If you guessed wrong about their previous location and they're not there when you boot up Recovery Mac, try copying them over from the location you copied them to on the other Mac.