Wouldn't be nice if...

Yes charging is a lot less of a load than a constant lighting load. But it is an interesting thought.

Well, using LED's and running them at lower currents, you might be able to do that trick.

Have you considered putting a rechargeable battery in each house and using LED's?

How about a simple plug and jack arrangement?

A constant inductive type charging 24 hours, to a rechargeable battery might do it...

Yes a recharging battery system would do it, though as Cjack points out, it would have to be on 24/7, which from other threads, warns of not leaving layouts on in case of fire etc.  Then of course, is how to trigger the lights on, since  the inductive coupling would only be trickle charging the battery overnight.  So would need to have switches on each building or some master switch wiring which would be right back to holes in layout with wires.  Could get sophisticated and design a simple two level trigger switch. Low level charges, higher level triggers LED lights on. 

And Mr. Burfle, yes a plug and play would work, assuming the items plugs were spaced apart so structures would cover over the openings no matter how things were arranged.  But certainly would be doable if the area is defined say by trackage or table edges.

Fun mind game to play.  But as I read somewhere: "don't say it can't be done, because someone somewhere is already working on the solution".

Wireless switching for the lights.  One button, all the lights off.