I have a credit for $159.70 I am happy to sell for BTC equivalent $USD 125 or best offer. I will use a conversion rate based on the previous day's close of MTGOXUSD at http://bitcoincharts.com/markets/mtgoxUSD.html
6.805 $USD/BTC at moment.
I have not done this before but I am told by Virgin you would just need to give me your Elevate account info so I can transfer post payment. You can sign up for the Virgin America Elevate club for free I think - so no worries if you don't already have one.
expiry jan 2012
update: posted this on ebay, I have 100% positive rating with over 120 transactions, pm me if you want the link