Kool deal Beckdg. Yea as far as LED's go they have been around a long time. And now can be seen every where. Stop lights, the light bars on police, ambulance's, firetrucks, automobile tail lights and interior lighting, TV's. I'm currently working on a design for headlights that are LED based (reflected parabolic lighting). As far as they are emerging into the market, anything new cost more until it can be produced on a mass scale and the prices for the materials come down.
Here's a thought for ya. Imagine the scenic back drop that some use in their cages, aquariums, and other pet housings, they are very realistic due to the imaging technology we have now. But lets add LED's to it? Well a new form of LED's called OLED's (Organic Light Emitting Diodes) this tech has the ability to produce HD quality images in a very thin layer. It could be a Mylar or vinyl sheeting that could be applied directly to the back of the tank and you would have unlimited images as your back grounds. In fact you could have a looped video showing the jungle scene with the wind blowing and the trees moving ect. You could even incorporate a moving stream that would (if placed right) empty into your waterfall you made in your tank. Pretty cool huh? The tech is already out there, but alas the one down fall with the tech is that the screens have a short life span (any where from 3-5yrs) and is very expensive. It will be a while before such a product will be available at your local pet store.
But like I said the LED's have come a long way and have a long way to go. They are in every home in one shape or form. They are being used in many aspects from medical to combat weapons and everything in between. You can already go to your local Lowe's and buy light bulbs that use LED's in them to replace certain bulbs (limited selection right now), But that will change over the next 3yrs (was talking to a friend who works for GE).
Ok enough rambling from me. LOL
Curious on the OLED's? Here's a place that will explain it and show you some examples in easy to understand terms:
HowStuffWorks "How OLEDs Work"