After a discussion on the perl-qa list, and being blessed with a few hours free time, I wrote a shiny thing, which, given a module name on the CPAN, will find all its dependencies, and their dependencies yea even unto the Nth generation, and display a nice shiny report on their CPAN-testers results.
I expect it to be useful for authors trying to decide what to depend on (you don't want to depend on stuff that itself has fragile dependencies) and also for people trying to figger out why the hell some random module won't install.
To see half the CPAN, try pointing it at Angerwhale.
update: it now calculates the likelihood of a trouble-free install, and has been made much faster by having a local copy of the CPAN testers database and moving to mod_perl