TAPESTREA is a similar sound editor that could do some interesting spectrum editing. It was available from the CCRMA repository for Fedora. I enjoyed using it but haven't been able to compile myself.
http://taps.cs.princeton.edu/ISSE appears to be a child of TAPESTREA, with some more advanced and smarter features but does not seem to include some of the fun, interactive features of its parent.
If anyone knows the secret of compiling TAPESTREA for 64-bit Fedora, please let me know.