I've created a patch to support stopping the FM Radio application (D-Bus support for FM Radio has been integrated by Martin in SVN - I don't know when he will release a new version with the D-Bus interface, but the support is there). It seems like FM Radio 2010.03.15 will include D-Bus support from what I can see in the SVN history for the project.

There does not seem to be a source code repository for Sleeper (yet?), so I just grabbed the latest source, and did my patch on top of the current release. I've published the patch in the newly-added section "Patches" on Sleeper's wiki page.

Tom: It would be nice if you could merge this patch in one of the next releases and remove it from the Wiki page after a version of Sleeper with this patch merged (if you don't object to its contents, of course) has entered Extras-Devel.