I think ShareDir can work for you with care and blib (I haven't done this so, consider it salted/untested). You'll just need to run something like this before using the code in dev:

 perl Makefile.PL && make
 # then-
 use blib;
 # or
 perl -Mblib ...executable...
[download]

The blib stuff should function as production code would; i.e., ShareDir will find the right things in a relative fashion under, I think, blib/**/auto/... The pain being that you might need to run make all the time to see code changes.

For Catalyst, take a look at the source code for home() in Catalyst::Utils. It uses the presence of a Makefile.PL (or other dev env markers) to determine the root of the application (local/anywhere v formally installed) and where it can find its files relatively. This is a bit of a systems/deployment decision more than a code choice though so I'm not sure I'd recommend it.