Also, Ovid has just written Class::Sniff, which he detailed in a series of blog posts:

1. Class::C3 Wierdness?
2. What Did I just Write?
3. Class::Sniff Now Detects "Unreachable" Methods
4. Class::Sniff Reporting and Exported "Methods"
5. Class::Sniff Now Detects "Duplicate" Methods
6. Detecting Long Methods Without PPI
7. Class::Sniff Notes

Not all of these entries relate directly to your problem, but I always find it interesting to follow the train of thought of module authors while they're initially developing a module.