For testing my pingback server and being able to link to other blogs I have implemented a quick'n'dirty pingback client.
It's written in php5 (and can be very easily ported to perl) and contains auto-discovery of target links as well as their
coresponding pingback-xmlrpc server-url (via HTTP-HEAD and fallback to HTML-HEAD).
To test it (and as a result of it also the pingback server) I had to link to an article in my blog. There. Did it.
By using this client you can call pingback entries to your URL without your blog software supporting pingbacks. Increcibleously!