You can build whatever custom circuit you want to control decorations and non-motors, is what our team decided. Rule <R04> (I think) says you cannot control "output devices" with custom circuits or COTS electronics. We decided that LEDs are not output devices.
If you want to use spikes, you can easily control each of the two leads directly, so that's LEDs per spike. See this thread:
http://www.chiefdelphi.com/forums/sh...ad.php?t=89207