After some measuring and extrapolating, I've concluded that the LED matrix I'm including in the helmet's faceplate will contain either a 24 by 40 LED matrix or a 24 by 32 LED matrix (that's 960 or 768 LEDs respectively).
From the way you were talking I thought you were going to do a BIG matrix. 24x32 is fairly modest around here.
I was thinking of using MAX7221 LED driver's for each grid of 8x8 LEDs.
Due to my lack of experience I have no idea how to go about wiring or coding something like this; so any help, advice or criticisms would be greatly appreciated.
(I should probably add that I took an introductory programming course last year, and that my dad is a computer programmer so he should be able to help me if I get stuck with the coding part of the project. Also, I'm going to use single color, 5mm, red LEDs.)
If I was you I'd buy prebuilt 8x8 modules and fit them together. It'll save a lot of work and end up far neater. 8x8 LED matrices don't really cost more than buying the individual LEDs.
You can fix one MAX7221 to the back of each module then all you need is power and SPI bus from the Arduino to control them - just six wires.