When scp is too slow, and rdist over scp is more functionality than you need, look at sftp.
The sftp command set will be familiar to anyone who has used ftp.
Sftp allows use of a batch file, and it has a tunable buffer size. The -B flag controls the tunable buffer size and is useful when copying files over wide links that have latency. Tests over a DS3 have shown 20% throughput increases simply by increasing the default buffer of 32K. There are limits, and you can experiment on your platforms. Choosing a value too high will result in a message such as, "Outbound message too long 262169".