E3D news - hope it’s ok to post here? > li’l tiny prints with 0.15 nozzles - nearly impossible to engineer, but not quite 
http://e3d-online.com/High-Res-015-Nozzles
But theres something that troubles me, can a 3d printer/slicer can actually use it?? Microstepping can be a problem sometimes
@lightshadown most printers can make movements smaller than this. It’s more about being extremely level and having a rigid frame.