Does Python have a BPEL/BPM-style workflow engine like Ruby's ruote?
This doesn't seem to be it, but I would love to have a workflow engine which is designed for long running tasks, with periodic human interruption, conditional flows, and so on.
I'm not sure how they compare to Ruby's "ruote", but there are quite a few Python workflow managers and libraries out there.
GC3Pie (http://gc3pie.googlecode.com/) is a Python library for running many-task workflows featuring interruptible execution, interfaces to SGE, PBS and LSF clusters, and composition operators to build dynamic task dependencies (so, not just DAGs). Disclaimer: I'm one of the developers.
NiPyPe (http://nipy.sourceforge.net/nipype/) is a Python workflow engine especially targeted at Neuro-Imaging processing (but the core framework is generic, as far as I understand).
I'm pretty sure this list is not exhaustive: many people seem to be re-writing the same core functionality, coming from different fields and/or with slightly different requirements.
This doesn't seem to be it, but I would love to have a workflow engine which is designed for long running tasks, with periodic human interruption, conditional flows, and so on.