let me dig some branch I have once made but haven't decided to share since it was not really "useful" yet (results from hrf_estimation haven't improved to say the least but actually some were somewhat interesting).  
but there (now a PR ) there is a ```simple_hrf_dataset``` function which could be reused may be to some degree here?  ideally should be RFed to just again take the events and description of 'HRF' possibly per condition of interest -- would be kinda cool to allow varying HRFs in such simulations.  See #191 for my now somewhat aged attempt -- it did provide working interface for hrf_estimation with some "advanced" (may be incorrect ;-) ) feature of groupping different types of events so they could get the same within-group HRF