I've been thinking about a couple of different options and here is what I've come up with:
1. You can still grab the file and head to Kinkos to get it printed big in black and white.
Jenny at Little Green notebook has a great post about big prints for little cash: - She actually scanned a photo and had it blown up.
LGN also has a great way to hang big art on the cheap.
You could split up a big piece of art into several parts and hang them separately to get the triptych look.
2. You could take this a step further and add to the black and white copy post printing. There are watercolor pencils that would be a fun way to color in the octopus. You could also paint over it in translucent paints, you could dye the paper, stain it with tea for an antique look, etc.
Also - PicMonkey kinda took the place of Picknik for a lot of people, and while I haven't used it inside and out, it is pretty okay. Or, if you are lucky and have Photoshop, you have the world at your fingertips in terms of photo manipulation.
I'm curious if anyone has done this project. What have you discovered?
UPDATE: I found someone who actually did it!!! Go here to see her finished product. Looks great! Thanks for the shout out.