I can't help but can comiserate with the lack of options for distributing applications. I would recommend you do your best to replicate your client's environment; even if that means using the system perl on MacOS. If all you're needing is to be able to install locally using cpanm (e.g.), then you don't actually need perlbrew. In addition to this, you can do your own "fatpacking" if it's "pure Pure" - just distribute your own tarball/zip with a thing/bin and thing/lib - if he can follow instructions, he can: update PATH and add PERL5LIB to his environment (or write him a starter shell script to do that). An additional lament is this: why aren't Perl modules that require compiled things on MacOS offered as packages in via brew like they are in every other package manager; brew definitely builds stuff, so it's not a matter of maintaining upstream binary packages. Whatever the answer, I'd love to see the Perl Foundation get more involved in enabling better Perl application distribution options for MacOS and Windows. This alone would get a ton more users to our "base".

This Platypus thing does look interesting, I am going to have to play around with it.