Approximately how many LEDs can you power from a wall wart?
Are you wiring the LEDs in series, parallel, or series/parallel combination? If combination, how many LEDs per parallel set? What are the output current and voltage ratings of the wall wart? What are the current and voltage ratings, should be on the package, of the LEDs?
There's no way to answer your question without this information.
Len
Just single lights to be used in buildings and etc?
Okay. If your going to put 1 LED per building, all going to the same wall-wart, are you going to wire them in series, or parallel?
(http://www.l-ateliergourmand.com/thumbnail/l/led-lights-parallel-or-series-wiring-on-serial-and-parallel-wiring-6.png)
It makes a difference.
Len