I've started thinking about manipulators for this stereotax.  There's a good review on open-source approaches for manipulators here:

https://www.researchgate.net/publication/327737857_Approaches_to_Open_Source_3-D_Printable_Probe_Positioners_and_Micromanipulators_for_Probe_Stations

I doubt I'll design my own, but it might be possible to bolt one of the open-source designs in that paper onto the side of this stereotax.  The aluminum base-plate is easy to mount things on.  Here are some photos of the 3D stereotax with some ThorLabs optical posts mounted to the base plate: