The Aztec costume is, I'm told, about finished - I'll post a picture of it next time I write.
As I'm going on holiday for a couple of weeks, it'll have to wait until I get back (unless I get really bored and find myself in an Internet Cafe. Unlikely). We're off to Greece; a week touring and looking at antiquities, followed by a week on an island.
The French historian Jacques Soustelle once remarked that a crowd of Aztecs would have looked like a crowd of Athenians, and I suppose there were some similarities: like the Athenians, the Mexica lived in what was essentially a city-state surrounded by other notionally independent city-states, in a mountainous country, and in classical times at least continual warfare was pretty much the norm. And they both favoured cloaks as the main garment for men, although I think Greek costume was less strictly prescribed than Aztec garb.
But I'm always a bit wary of comparisons between unrelated peoples. I've seen the Aztecs compared to the Romans (because of the way their armies were organised), the Japanese (fierce warriors who believed in fate and loved flowers and poetry), the Egyptians (pyramids!) etc etc. I've thought myself that there are interesting resemblances between Aztec and Tibetan culture; Tibetan Buddhists may be peaceful folk now but their iconography hints at a blood-curdlingly violent history. Nearly always, however, these comparisons don't stand up to any sort of scrutiny. Aztecs and Egyptians both built pyramids, but they weren't the same thing at all. Greek though, which so often is about drawing sharp distinctions between categories, is nothing like Aztec thought, which tends to emphasise the oneness of things. So I'm not sure you can use one culture to give you much insight into another.
I'm not going to try. I just intend to enjoy my holiday. Though the idea of setting a book in ancient Greece did occur to me at one time...