The origami crabs have arrived safely, after a delay because the British customs office was closed for the weekend. Which reminds me: When I started telling a friend what I was doing, he asked, "What is origami?" So when I was filling out the export form to describe what I was exporting to the UK, I first wrote "two origami crabs", and then added "(paper, folded)" in case the export agent might think that origami is a species of crab.
I didn't quote from my email responding to Dave McKean, because I wanted to keep the story short and not boring to non-folders. But since many folders are reading this blog, I'll quote most of it here:
I have helped people with origami projects before, but not with such a time constraint! I think I can do it, though, but the requirement for white is a small concern, which I will explain.
Folding an object with many appendages, such as a crab, from a single square of paper without cutting is a complex process with many folds (424 steps for John Montroll's crab), which builds up many layers. To prevent bulkyness and a tendancy to unfold and look fluffy, such models need to be folded from a thin foil/paper composite. (On the Origami Database web page where you saw my model in gold foil/paper, there is a photo of a crab done in thin paper, which is not as crisp.) The malleability of soft metal and crispness of the paper combine for a good result.
I don't have access to white foil/paper, but the model can folded so that the white paper 'back' can be the 'front', and the foil side in back. I have 12 3/4 inch squares of silver foil/paper that I can use. (The foil side is actually a light-grey/silver speckle pattern.) My guess is that the model will be about 3 or 4 inches wide.
If you carefully examine the photo of the crab that I folded, you will see that a little white shows at edges at the legs. When I reverse the foil/paper, a little grey/silver will show in these places. From my experience in photographing origami, I predict that depending on the angle of the light, these edges will either look like grey shadow or silver highlights. I hope that this will be satisfactory. (You can daub these edges with thin white paint, if you prefer. I can include some extra paper to experiment with.)
If I learn anything more, I'll post it here. And if you find something, post a comment here. Details are often found in blog comments.