That would be a useful feature, and we may eventually be able to implement it. It's a little tricky because even if you remove the files (with, for example, rm), the processes can still continue to write to the file descriptors as long as they have them open.
In the meantime, you could configure logrotate to be more aggressive about compressing and deleting old logs. By default, AppScale configures logrotate for each deployed application
here and for the rest of the services
here. Is there a set of log files that are particularly problematic, or are they all large?