Re. dbuscron,

This is not really useful information, but: on my "normal" N900 I have neither dbus-scripts nor dbuscron. On my "spare" N900 I installed dbus-scripts (however without writing any actual script) and didn't notice any (measurable) battery hit.

I later uninstalled it and installed dbuscron instead, mostly for philosophical reasons (listening to both session and system bus running a single instance of the daemon). Again, I (still) haven't written any script for it (but the swap recycle is a good candidate).

I have noticed no (measurable) battery impact with dbuscron either. Admitedly, the spare N900 is mostly unused and in off-line mode, so I charge it like once a week or so..

I suppose that the daemon itself (i.e. the listening on dbus) doesn't use much, but depending on which events trigger your script(s) the battery impact may be much bigger..