Thanks guys. So the jury's out on this one. I have researched both on the net and it is hard to say although I notice that all the pics of the Masked Crimson Tanager show them having a very dark underbelly, which this bird doesn't have?
I've seen my share of wild masked crimson tanagers and a reasonable number of captives too. The difference between the male and female is rather negligible. If this is a masked crimson, something went seriously wrong in its development (belly+mask). However, this looks exactly like I'd expect a hybrid masked crimson X Brazilian would look. Hybrids between different species in this genus are well known...