I have a pixel trees (of sorts). Not megatree format with strands but I simply wrap the trunks. It may be another option for you.
The trees are wrapped in strings of 1000 pixels (power injection every 2 strings). Consumes a lot of power but always a talking point.
Just have a look on Ebay for them. I bought an NEC short throw
Can't find much on Ebay tonight, this might be similar
I've tried and failed with those cheap projectors off Ebay.
Recently purchased a 2nd hand NEC short throw projector which had been installed at a Uni. Cost $100 and has 1500 hours left on the lamp which is tons. Brightness and image quality is far better than the cheap LED ones I'd say...
Two things I've tried with success
1. Silicon some cable tie clips (make sure you remove the backing paper / double sided tape first) to the tiles. Then cable tie lights down. They need replacing every 2-3 years in my experience.
2. Use fine tile wire hooked in under the tiles (twist around...
Here is a few from my show..
I have a number of power outlets around the exterior of the house switched together so the controllers come on around 8.15Pm and switch off at 12.00AM. All run back to a main switchboard (used for everything not just Christmas)
2016 Megatree controllers (x2)...
Boondogs - are you looking for something you can set the temperature threshold?
If so have a look at something like this: http://www.ebay.com.au/itm/12V-1-Channel-Control-Switch-Thermistor-Relay-Sensor-Temperature-Detect-Module-S-/191736124877?hash=item2ca45d15cd:g:xjwAAOSwpRRWmaUH
The c9 covers definitely fit. Here is a picture of them.
You will need to hot-glue each one onto the LED, as they will fall off without it.
(Alternatively, Ray glues them for free if you are prepared to buy new strings).