I work alot w/ genetics, and perhaps I can get my friend to look here as he is lead geneticist for nc state, but albinism isn't just a lack of color or pigment. it is the lack of a certain color (generally melanin which produces varying shades of black and brown). Such as my albino Boas, though they are true albino's they have varying shades of orange and yellow left. My anetherystics have no red pigment (ie no brown) so they apear black and white (w/ varying degrees of yellow) Yellow is produced by xanthin, so U would need the axanthic gene to remove that color. Basically U may have seen color morphs already and not reall noticed. or just seen one that looked different, but didn't register as something unique. I believe it is and will be very hard to isolate genes, because mantids naturally use diverse color genes to survive. That is why U can get so many varieties of color from two mantids. the offspring disperse, leaving the gentic weak to be picked off early, ([hypothetical situation]in this case the weakness is color) the greens survive more efficiently in this area because of all the foilage, but if two greens mate they still produce brown's. the reason being as nature knows things change. perhaps this was an exceptionally dry year, so the greens get picked off in great numbers and the fewer browns survive to mate.
I do believe that genetic anomalies do happen. and the only way to pinpoint one is to take what may be a unique or desreable color and breed it. Then U must take the offspring and breed them back to eachother. By doing that U can check for anomalies. Then U can begin on breeding hetrozygous and homozygous forms. The most stunning generally are a combination of recessive genes. Such as an anery/albino. That would most likely be solid white. Or Solid white base color with translucent yellow, or lavender markings where the pattern was. Hope this helps.