No worries Katt... of course melanin can produce a brown pigment. But so can xanthophores. I'm fascinated by genetics and pigments too.
Take kenyan sand boas for instance.... calling Anery kenyans "Anery" is kind of incorrect, since their orange pigment is produced by xanthins, not erythrins. Calling them axanthic is more correct. The same *can* (but is is not always) be said about brown. Xanthins in abundance *can* create a brown pigment.