How big is the area you want to add the lights? How many colors? I bought a small circuit board to run HO scale traffic lights... I'm pretty sure the guy said there was a random feature on them. Downside is they cost about $25. Something else you might consider is going low tech. look for tree lights in dollhouse stuff on ebay, and put a slow moving spinning wheel between it and your buttons. The spinning perforated wheel will keep most of the blinking lights off of your panel, letting light thru where ever it's perforated at the time. If you can, try and put a photo up of the panel next to a ruler. Knowing the space available helps a lot.