There is a two page article in the Scandinavian Traveller about Travel Cash.
The option to online exchange left over Euro to USD is kind of nice but for the rest I'm not sure I want to carry around another card. Especially prepaid to some currency might end up in losses over the time if the exchange rates develop not in your favor - or in making money out of it. But not sure you wil get ever back money of the card... You probably have to spend it.
Could be a nice option for kids and teens travel on their own.