Photoshop :: Making A Brush That Uses 2 Colors

Using CS3

if it's possible to create a brush that uses two colors rather than one with transparency.. I know about the foreground/background color jitter within the brush options, but I need it so that when I paint using this brush it actually lays down two colors per "stroke".

Actually, I imagine what I'm trying to do would be considered cloning rather than brushing. I messed with the clone stamp tool a bit, but couldn't achieve the desired effect.

Lastly, this is what I'm trying to do:

I am trying to duplicate a large amount of dollar bills, and I want them scattered and at random angles.. something the brush dialog offers the right options for of course. Manually placing them and rotating is definitely not an option. When I paint them in using a custom brush, all the dollar bills I've painted in already show through because the white areas of my custom brush translate to transparency - the result is an indistinguishable mess of black.