This might not be exactly what you are looking for but here is what I've done to get noticed. At my company we aren't trying to do get guest blogging opportunities but have high quality people guest blog for us. For us we are are a ninche specialized market and the people who are experts and influence don't blog and told us no no no when we approached them to guest blog.
But when we asked for an interview..it changed everything. So we asked to do an interview over email. A simple INTERVIEW REQUEST in subject line did wonders. But remember if you are asking for an interview never send form email. It must be personal and show you know subject.