So what you want in fact is a really stable distribution of Perl? If what you needed works only in Perl 5.5.x, even that branch is still maintained, or rather, still mostly compiles on a lot of platforms. If you move within Perl5 releases, some breakage is to be expected in my opinion - that's why Perl 5.5.x still has a "maintenance branch", even though 5.5.4 had as its main change some fixes for gcc compatibility.
The Debian folks never got the spirit of Perl in my opinion, as they never released their modules and applications onto the CPAN, which makes integrating their modules with newer Perls quite difficult. But what you consider a "quite complicated upgrade path" I consider a triviality, and have made it into a rule: Never change your vendors perl. Upgrading or changing your vendors perl on your own will inevitably lead to a broken Perl installation and most likely to malfunctioning system tools too. Perl itself can live quite happily in different versions on the same machine and you should take advantage of that instead of fighting against it. Using Debians (or whatever other) package manager to manage Perl modules is, in my opinion, the wrong way to do things if Perl is central to your objectives. I know that others go the other way and maintain everything through their OS' package tool, but to them, Perl is merely one tool and not the central reason to run an OS.
The "very strong movement" is there because the Perl core is too big, and that's a good reason to want Perl out of an operating systems core. Perl 5.8.10 or 5.8.12 are supposed to get a much smaller core. Anybody doing non-trivial programming in any of the shells incurs a much higher development/bug hunting cost than (competently) using Perl. For a Linux distribution, the higher development cost may pay off in a smaller distribution size.
In the end, I think if you stick with Perl 5.5.x, you get the "real basic and stable" part of Perl on which you can rely. But, as the quote goes, biologists have this special word for "stable": dead - you can't have both, a live and evolving use of the language and its features and a stable set that never changes.