I'd like to see a tool for finding trust paths between PGP keys. Something like http://pgp.cs.uu.nl/, except not using a web site. I would like to be able to plug this into an e-mail program, for example. It could make use of the keyserver keyring, but I would also like to use it on other keyrings. For example, making queries only on the Debian keyring would occasionally be useful.