Is Kim Dotcom's "Megacard" a viable possibility for bitcoin?
This type of product has been tossed around since at least May 2011 when MagicalTux was the new owner of Mt. Gox.  They no longer discuss it.

BitInstant "leaked" such a Mastercard in Fall 2012.  They claim it is "seeing progress" but there's nothing yet.

There are similar cards.  Peter Schiff's Euro Pacific Bank offers a gold-backed debit card where gold funds are sold when using the debit card to make purchases using fiat.  But that is not available to customers from the U.S.