Was it this thread where someone recommended installing 1/4" drywall over wood paneling? I immediately found instructions that seemed self-explanatory, although it left me with more questions than answers. It mentioned outlet extensions, but it took a while to track down these:
STEEL CITY 1-Gang Square Metal Electrical Box Cover
It is $1.20 at Lowe's, but hopefully they have more than 1 in stock if I ever need any!
I couldn't find instructions for a while. You remove the face plate, unscrew the outlet, screw this over the gang box, pull the outlet through, screw it into this, and install the face plate.