I agree with the thought of bringing the wort up to boil after mash out... and then leaving it for a few hours with the burner off.
I have done this a few times with no noticeable ill effects. The flavors are a tad different, but only really noticeable when doing a side by side comparison.
Even the best planned brew day is sometimes interrupted by a sick kid at school, or a need to hit the store for lunch groceries!
Also, I know a person that has an all electric system, and due to time constraints, mashes the night before, brings the wort just up to boil, covers, catches 6 to 8 hours of sleep, and has their electric system on a timer to turn on 20 minutes before they wake up. That way the wort is nearing boiling and they do not have to wait the 40 minutes for their wort to heat back up. (Still need to be in attendance to ensure no boil overs, however.) It is a bit more work overall, but it fits into his schedule. Kind of seperates his brew day into two 3 hour blocks instead of one steady 6 hour block. When you have kids... haveing 6 hours available can be hard!
So I say go for it if you like!