Gizmodo is reporting that Apple has begun refunding up to an extra 15% of the purchase price of the 27-inch iMac to those customers who bought defective units.
The news broke yesterday with a UK-based Apple Authorized Service Provider/Reseller claiming that Apple is out of 27" screens in Europe, and they're dealing with a waiting list of customers already. So they're now offering up (to only certain customers so far, not an official policy) not only a full refund, but an extra 15% on top of the price, roughly $300 on the cost of a $2000 iMac.
Gizmodo also points out that the refund doesn't include sales tax or shipping costs, so some of the 15% covers that as well. You won't be able to make money on this, but Apple is apparently offering up a small bonus to customers inconvenienced by the issues.
Earlier this week Apple released another firmware update to address the flickering screen issues with the 27-inch iMacs but it seems that has not alleviated all the issues.