You have to create a new message type.
We don't plan to offer our own "Stamped" versions of the std_msgs as Header itself is a bit too tied to a particular implementation of coordinate frames (it's only in std_msgs for historical reasons).
The contents of std_msgs are designed to be building blocks not standalone messages. A well designed ROS message will stand alone and can be processed regardless of where it came from. The topic can add semantic meaning but should not be necessary for interpreting the data. For example the sensor_msgs/LaserScan contains all the information required to process it as a laser scan regardless of the topic. Whereas a message of StampedFloat cannot be interpreted w/o knowing the context of what the message is representing.