I couldn't agree more. You can buy this stuff from Amazon. I'm pretty sure it's the same stuff from Kraft, without the anti-caking agent, but it's about the same price as buying an extra box and ditching the noodles.
You can find them on Amazon, several different brands. Not too expensive either:
You can just buy the cheese powder and make your own.
Cheddar Cheese Powder, 1 lb. by Barry Farm https://www.amazon.com/dp/B00016LZT8/ref=cm_sw_r_cp_apip_6Kkcsp2HlsDGA
This is as close as I have found.
http://www.amazon.com/Cheddar-Cheese-Powder-1-lb/dp/B00016LZT8
You can buy cheese powder at amazon which is pretty damn close. I just got my third bag.
And then there's this. Spray-dried cheddar, and they have lots of varieties and other flavors.