Why should volatility be problem?If you are so afraid of the Bitcoin price fluctuations,than why not just sell your bitcoins for fiat,right after the buyer pays you with BTC for the domain name(after 3 confirmations).
If you ask me,BTC price volatility won't be your main problem.Your main problem will be finding buyers that are willing to pay for a domain name by using Bitcoin.
By the way,do you plan to use a crypto payment processor,like Bitpay or Coinpayments?