Buy some Flat Spray paint,Grey,Brown,Green or some black,Maybe paint a base color like grey or black,then hold small leaves in places and paint them leaving thier imprint on the case,get inventive.
Im thinking Grey and Black will blend with the tree you put it on if you stripe it like bark.
I also use the pelican 1120, I have just been using them "as is", black...I am in the same boat, I wish I would have sprayed them before cutting my holes etc.etc. I think over the winter, I am going to bite the bullet and buy some of that camo "cloth" sheeting and ever so carefully fill in all of the exposed black area's on my pelican.
I won't use the camo tape (duct) because it is usually has a very glossy look to it and from a distance if the sun hits it , it will stand out like a sore thumb. I usually just use cheap walmart brand flat black,brown, and green paint with a touch of primer gray to paint my boxes. Find you a maple tree or a oak tree with a good size leaf, say about as big as a coffeecup and then i use the leaves as stencils to paint around to give my box some camo/woodzy look. Don't overdo it though, just enough to blend in, not stand out. Thanks DC