I drew mine up and cut it on the laser at work. You would have to find a job shop with a laser to cut it for you. I do not know how common that is around you. Some places do not like cutting single pieces and will price it very high to discourage you.
If you daisy chain those smart receivers you can get it up to 28 ports maybe 36 if you converted port 1-4 to smart and then hooked up receivers to the serial port.
Your power supply will be your limiter. My 12 volt regulated pixel use 0.36 watts at 50% brightness white. The power supply is 350 watts but I do not think you should max out the power supply so if you take 80% of that which is 280 watts divide that by 0.36 watts/ pixel leaves you with 777...
To add to this is is not just a audit it could be an audit from every state so a small company that was doing everything correct could end up with thousands in legal and accounting fees to prove they are innocent.
Another opinion on the tree. I use a 360° tree but for a number of sequences I use a 180° sub model. I think images look better when there is not any light on the back side of the tree. My wife likes to look out the window and see the lights on the tree also.