Actually, [GSF] Ghost used the standard 256x256 size texture, and then just made the interior larger to fit the scale. Anyways, remind me to add this to my tutorial later.
A 1x1x1 brick in Blockland is the same a a 0.5x0.5x0.6 cube in Torque Constructor. To make the 1x1 brick stud texture fit to that scale, it must be a 16x16 pixel image. Note: If you're using a texture with 4 bricks, the size would then be 32x32 pixels.
Sorry about the noobish explanation, I was writing it for the tutorial ;)