That is a very good question, Arctic... An engine failure in conditions which are close to your operating IMC minimums is definitely very difficult situation. There isn't anything special which you can do, just fly the plane using best glide speed, try to start engine again and send a mayday call... You could also try to plot your position to VFR chart using nav aids which would give you a better picture of the ground below. Surely it helps too if you are already familiar with the scenery and you have been flying in the area in VMC conditions before.
Of course the MSA will give you good information as well. I would try to look outside more intensively perhaps when gliding below MSA... if you are only 300-400ft feet above the estimated terrain altitude (location plotted from VFR-chart for example) but without visual contact, I would perhaps select the flaps fully down, slow down near the stalling speed and prepare for the impact without the contact but still trying to look outside for visual clues. This would at least give you a smaller speed at the time when you hit the ground.
The same difficult situation applies for night VFR flights as well... Think about the situation where there is overcast layer, not many lights visible on the ground and a very dark night...
Ahh, the wonderful world of flying single engine pistons...
Happy landings,
-AM-