I like David Howland's answer with one caveat: a keep and a stash are different in nature. A stash is merely a patch (i.e. set of diffs) stored in a place...it has no influence on git's history. Keep (which I think is most analogous to git's commit) writes changes to AccuRev's database.
To see this in action, keep a change to a file you intend to stash, then view its history: it will include your "stashed" change. This will end up polluting the logs.
One option is to create a new workspace whenever you start to work on something different in parallel with your current work.
In summary, I don't think AccuRev has stash/shelveset functionality.
Update
Eclipse's Create/Apply Patch functionality might be what you're looking for:
- Create a patch file (in essence a stash/shelveset)
- Then re-apply that patch file to push back in the changes.
For whatever reason it doesn't seem to be matching up the diff's index's file locations correctly, but at least it's a step in the right direction.