I just looked up "whitewash" and I don't see anything too disagreeable. It's basically chalk. And every once in a while some random thought goes careening around my brain folds (picture a bobsled run, only wet, wild, wooly and... squishy) - and that thought is: to stay white, it will need periodic treatment. You MAY be better off with a low-rent, but easily renewable finish. I mean, picture a really hard, scratch-resistant white epoxy finish. With some dirt and grayness inevitably ground right into it Alas, even epoxy is NOT THAT HARD, really. But it's hard enough that repairing it would be a major pain in ye old Gluteus Max. Whereas something dumb & simple like whitewash would require prepping for the redo - 30 seconds with a stiff toothbrush per fret, maybe?
Surely you can get some holly wood, I know Jimmy Page just got an all-white guitar made of holly. It looks to be hard "enough." This is the luthier, a different guitar but he seems to like the stuff:
http://www.parsonsguitars.com/image-gallery/parsons-guitars-2013_white-mare.php
http://www.sizes.com/units/janka.htm
If you can find a suitable piece of holly - DRIED - I'm pretty sure LMII would radius and slot it for you - http://www.lmii.com/products/tools-services/shop-services