I haven't seen alt-photo processes used on urns ,
however, I have seen alt-photo portraits on 
gravestones.  There was a time when Daguerreotypes 
of loved ones were set into funerary monuments.  
The modern equivalent is made with a photo-ceramic 
process.  I made a Dag once using one of these 
gravestone portraits as a subject.  I would have 
made others but when I returned to the "grounds" 
a year later, someone had taken a hammer to them.
Phillip Murphy