Is there anyway to guess at Vaarsuvius's gender? I know the author has stated he won't give it away, but is it perhaps likely that there are hints, and indicators I may have missed in the comics.
Is it possible to tell? Or is it not?
Q: Is Vaarsuvius male or female?
A: I will never reveal the truth! Bwahaha! Keep in mind that while certain other characters might refer to V as being male or female, that simply reveals their perception, not the actual reality of the situation.
The first time I heard someone question whether V was male or female was right after I posted my first strip. A friend of mine asked me about it; at the time, I simply answered. Luckily for me, that friend has not chosen to reveal what I said then to the world.
At the time of the lime green boots strip, there was a thread separate from the main discussion thread where someone said how nice it was to see two women adventurers who were so different from one another as V and Haley. Brief debate followed, but there were very few posters in those days. I don't think it made it to 12 posts.
By the comic with the belt, I was aware enough of the confusion that I had already taken a poll among an IRC gaming group I was in at the time and asked them what gender they thought he/she was, and the results were split: 4 thought V was a woman, 2 thought V was a man. So I decided to swing the perception the other way with my next strip.
Vaarsuvius's gender is intentionally ambiguous; it's a joke on/with the readers. Therefore, the question you asked doesn't have an accurate answer. Both? Neither? We may never know. Rich Burlew goes out of his way to preserve the secret, from the readers, and and even other members of the party.
Ambiguity about V's gender is such a well-known joke that it has its own shoutouts, such as this other elf from Looking For Group whose gender is ambiguous (though only to the other characters, in this case).
Well, since the author has explicitly said that the gender is ambiguous, even hints you think you've found in the comics probably can't be seen as definitive, since Rich Burlew can retcon it away if he feels that he accidentally pulled the reader towards one answer.
I'm going with "impossible to tell", since that is the express and explicit position of the author.