Generally multiple currencies aren't accepted and the volatility is much lower. You probably couldn't make a profit on normal consumer goods that have a return policy. For this to work you'd need potentially extreme currency changes over the course of a few weeks.
I don't think accepting multiple currencies is a requirement to do what you are saying. But I think the real answer is that you could do this with other currencies but it isn't profitable and the only reason it looks like a reasonable scheme with BTC is because of the large price movements which as it grows will lessen making this a non-issue if it even is right now.
