How to make pancakes/crepes without eggs nor any liquids besides water?

Given your updated criteria, what about using powdered milk for crepes and pancakes? Powdered milk tends to be very inexpensive. You can usually find in in the baking aisle at groceries in the U. S. The powdered milk will last you for a long time.

You can also get powdered eggs. Just google for them.

As Martha astutely commented below, look for recipes for pancake mixes that require adding only water and pack those.

Since you're actually trying to find a lightweight, long shelf-life alternative to eggs and milk, powdered milk and powdered eggs are probably your best alternatives.

If you want to have a mix-and-go arrangement, you're going to need dough conditioners and fillers that help prevent gluten from forming when you mix with liquid. Those would include ascorbic acid, alternative flours like malted barley or tapioca starch mixed with your wheat flour, and so on. Some will have other impacts on flavor and texture; buckwheat will add a nutty flavor and a crispier texture.

However, if you are more flexible, I would recommend rehydrating the milk and eggs before mixing in flour, to minimize the formation of gluten. You have the same need when making pancakes with the normal ingredients, so it won't be any different here. You need to gently mix in the flour and other dry ingredients as the last step, and let the batter stay somewhat lumpy, or, for crepes, let the batter rest for a good 30 minutes to allow the strands of gluten to relax again.

You seem to be concerned about cost. Powdered whole eggs are about $12-14/lb here, but this corresponds to roughly 48 eggs, which means you're paying roughly what you'd pay for higher quality eggs in the US (.25-30 cents each). Powdered milk, preferably spray-dried, is used at roughly 25 grams per 250 ml of "milk", so about .20 Euro per 250ml, which is cheaper than fresh milk where I live (though I don't buy the cheapest ones).

Additionally, you will need some form of fat, if not for flavor, for the purpose of preventing sticking to the pan, even with nonstick cookware. Also, it helps to have some in your batter because it helps reduce gluten formation. If you can't carry butter because of its shelf life, at least carry some vegetable oil.

I've seen water+flour+fat-only pancakes of the thickness of crepes in Chinese cooking, but these are not browned, so you won't get the same thing you're expecting if you're trying to make crepes.

If you don't mind crossing cultural boundaries, ground, soaked mung beans and ground rice are used in bindaeddeok, Korean style pancakes that are thicker than crepes but generally thinner than American pancakes. They can contain other ingredients in the batter, and are served with a dipping sauce made with soy sauce and vinegar, along with a few other flavorful ingredients (scallions, sesame, chili, perhaps). A similar concept exists in Southern India: Dosas, which are often made from ground urad dal, a kind of lentil, and ground rice, fermented at a warm temperature at least overnight, and often served with onions and chilies, in one of the simpler forms. Neither one of these resemble crepes in texture, however. In Vietnam, turmeric, flour and coconut milk are used in a stuffed pancake as well.

For pancakes, you will need baking powder, or, if you're using buttermilk powder instead, at least baking soda. For crepes this isn't necessary.

If your only concern is allergies to milk and/or soy, have you considered using coconut milk? It behaves much like cream in the 'close enough for jazz' sense, and can be thinned out as needed.

This is a job for dry masa flour. Having tried water-only pancake mix, a warm tortilla is infinitely more satisfying.

The masa suggestion is right on the spot. You just need to add water, not even salt, and you can make excellent tortillas anywhere - but they will not be crepes, definitely: different flavor. If you want to stick with flour and corn meal, I suggest you take with you a small bottle of olive oil. Stable at room temperature, a little goes a long way and even imparts some flavor.

As it has already been remarked, masa is not corn flour but the result of a much more complex process that makes the corn proteins more available (this should be useful to you).

The product sold as BisQuick http://www.bettycrocker.com/Products/Bisquick/Default and more generally as "biscuit mix" in North America works great, when camping, for both pancakes and dumplings - add more water for pancakes, less for dumplings. It has baking powder in it. Usually we have powdered milk with us when camping, and we mix up a little to make the batter with, but there's no particular chemical reason to do this, it's just a way to get some milk into people over the course of a trip. BTW, dumplings in a spicy stew or chili are a great alternative to serving them with bread, in circumstances where carrying bread is difficult.

If cost or availability are an issue for you, here are some sites that tell you how to make your own. I haven't tested these. http://factoidz.com/biscuit-mix-making-and-using-biscuit-mix-for-quick-meals/ or http://baking.about.com/od/pancakes/r/biscuitmix.htm or http://www.gardenguides.com/140102-quick-biscuit-mix-recipe.html

Preparing a thin batter without something that will congeal as it cooks (protein...egg) is going to be difficult.

Looking at your ingredients (but not the quantities) I'd think you were making tortillas. If you want to stick with the unleavened route, I'd try a dough that you can roll out thinly (or press with a tortilla press)

I would add some baking powder, and if you want it fluffy you can use sparkling water - the bubbles help it rise a little.

Both of these are cheap ingredients.

But I wonder - what is your motivation?

I make both vegan pancakes and crepes using:

-water -vegetable oil -white flour -baking powder -Sometimes I add flax seed

and I blend it before cooking them. The difference for the pancake and the crepe is how much I spread out the batter.