It sounds a bit like Tesla's idea he wanted to transmit power around earth free power for all ,lucky for the human race and all animal life he failed ,don't think its healthy living in a microwave oven same go,s for the frequencies he was planning on using .
Your idea for a passive NBTV receiver is nice you can do it another with a solar cell ,if you have a high brightness white led transmitting NBTV and a solar cell ...connecting the solar cell right to the input of your computers audio input it has the bandwidth ... it will give enough signal to view on Garys NBTV software with out any other electronics so i would think it would light an led hooked up to it ....so a few solar cells might light a bank of leds .
You have the modulating side done ..the moving of the disk is another problem a bank of transmitting leds might also give enough light to drive a small motor via its own solar cells .
For what you want to do never know experiment and find out .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.