Now I have tried this although it will not set up in the fridge into bars as you mentioned above. I have taken chocolate protien powder, 1 or 2 very ripe bananas, andd a spoon full of peanut butter and mix it all up. It taste really good and there is no cooking involved at all. You may be able to put the concoction into a plastic tupper ware bowl and take it with you, how ever it will not hardern. And as for gluten, I have heard that many bakers use yeast instead as it allows the bread, cakes ect to rise much better and fuller. As for taste, I could not say as I have never tried it.
Tobey