There are a number of pieces of software I've come across that install
"per-user".  That is, the installation process is designed to install
files into a user's home directory -- there is no "system-wide"
installation option -- so each user ends up with a separate
installation.  I'd like to package a couple of these, but I'm at a
loss as to what approach to take.

Is there an existing NetBSD package with "per-user" installation
characteristics?  I was hoping I could work off of someone else's
approach if something similar has been done already.

One example of such software is "a modified version of C alice":

  http://hippie.alicebot.com/