To access Cassandra from the spark-shell, I've found an assembly out of the cassandra-spark-driver with all dependencies (an "uberjar"). Providing it to the spark-shell using the --jars option like this:
spark-shell --jars spark-cassandra-assembly-1.0.0-SNAPSHOT-jar-with-dependencies.jar
I was also facing this similar issue but I resolved it using this method, it is both simple and convenient as compared to loading the long list of dependencies.
I found a gist with the POM file that you can download from here.
Now, in order to use the pom to create the uberjar you should do:
Note: If you're using sbt, look into the sbt-assembly plugin.