I sort of took up a challenge at International Skeptics (JREF as was) to look for Apollo impact craters, and having successfully found Apollo 13's crater in an Apollo 14 image (but tnot Apollo 12), I've been seeing what else I could find.
After much googling it seemed that no-one has yet managed to find the impact crater for Apollo 15's ascent module.
The official location is given as 26.36 N 0.25 E (decimal degrees), and while there is nothing obvious at that location on the LRO's quickmap site, 2.6 km to the west at 26.3727 N 0.1535 E there is this 20 m wide crater:
and zoomed in a bit more:
It seems like a good candidate because it is not evident on Metric Mapping Camera images taken by Apollo 15 relatively early in the mission, such as this detail from AS15-M-0416 taken on rev 16:
But there is a hint of it being there on Rev 60 in AS15-M-2050, taken after the LM impact:
Here they are together:
I've used the highest quality images possible from here
http://wms.lroc.asu.edu/apollo/browseThis is where someone tells me it was found years ago...