it sucks you can't buy this in Kit form, must be bought from an installer... i don't trust other people to solder anything..
Im assuming the n64 doesnt output native RGB like the SNES?
and then you need something that can take RGB as an input.. or an Upscaler.
my 57" LED tv has RGBHV input and supports 240p input... i also have some sweet 5K Lumens projectors that do the same