In principle, post-starburst galaxy spectral signatures (ie, A stars) last a similar time to shells (which last for tens of dynamical times), so we might find shells in post-starburst galaxies. I am starting to make pictures of all the very low redshift (for good physical resolution) galaxies in SDSS with post-starburst (nuclear) spectra. Here is one that is superimposed on the shell of a neighbor!
The post-starburst galaxy is at the center of the frame.
The last "complete" catalog of shell galaxies I can find is Malin and Carter (1983). To make a new one in SDSS would be a great service, but is perhaps beyond my patience, unless someone finds an automated shell finder (that is not fooled by spiral arms).
In other news, Alar Toomre and Milos Milosavljevic gave me more ideas for subject headings (starburst galaxies and double quasars, respectively) in my review.