Sub::Signatures has been uploaded via PAUSE and should soon be available at your friendly neighborhood CPAN. It supports:
It also has about 82 tests, though some are somewhat duplicates (long story.)
And from the POD where I do a bit of begging:
This is alpha code. Many people understandably do not wish to use alpha code in production. To get this code robust enough for production use, send me bug reports. Send me patches. Send me requests. Send me feedback.
For the impatient (like me)