Yeah, that would be cool. Might be hard to draw though, I would expect drawing a good sword-fight between two people who know what they're doing would be difficult, although given that most readers wouldn't know the difference between a good move and a bad one I guess it wouldn't be too hard to get away with.
Hmm.... who would I like to see facing off? Saya vs Nyos (properly this time) could be cool. I'd like to see more of Nyos, he hasn't really been in it much (plus I like his hair).