What record do we have of the length of supernovas?
I would expect that the further away a supernova is, the "longer" we observe it will be active because of an increased red shift.  Objects in the universe that are further away are generally going away from us faster than objects that are close, hence the increased red shift.  This increase in time due to redshift is very similar to the Doppler effect, where a siren is high pitched (and faster) when approaching you (e.g. blue shift with light), and low pitched (and slower) when going away from you (e.g. red shift with light).  The faster the siren is moving away, the more the effect (both lower pitch and longer time) will be increased, likewise with light.

Here are some sources that may help with what you are looking for (although I haven't been able to find a list exactly like you are looking for):

http://www.wolframalpha.com/input/?i=supernova

http://en.wikipedia.org/wiki/Supernova#Light_curves

http://en.wikipedia.org/wiki/Cosmic_distance_ladder#Type_Ia_light_curves

http://curious.astro.cornell.edu/question.php?number=49