Just an update.
I did finally paint my M4, and I'm pretty happy with the results. My only concern is how well the paint job will last after some field use.
I've uploaded the picture to the ASC Gallery:
http://www.airsoftcanada.com/gallery...hp?i=1994&c=10
It's hard to tell from the image, but it is a mixture of OD Green/Khaki/Brown. The green didn't show up too well in the picture, because it was taken indoors. This weekend I'll be able to take some pictures of it outdoors.
Thanks to all who offered suggestions and gave tips, it really did help me track down the type of camo scheme I wanted to use.