you want to run workflows with interdependencies on the same execution hosts on local memory

the ants registration can be made more robust by removing the Translate transform and using use initial_moving transform. i do like the transform parameters here:

https://github.com/nipy/nipype/blob/master/examples/fmri_ants_openfmri.py#L202

datasource can be combined into a single datagrabber. along the lines here: https://github.com/nipy/nipype/blob/master/examples/fmri_ants_openfmri.py#L667