Anybody else looking to form/join a podcast is welcome to network in the comments.
Having outside guests on your show who bring in fresh points of fiew is a great way to keep the content from degenerating into a series of inside jokes between you and your co-hosts.
I have found it generally isn't that hard to talk well known people to join you for a 45 minute recording since they are already usually working on finding ways to get their message out / build their brand, etc. already. Depending on the domain, a many of them actually pay people to help them get booked on podcasts for this very purpose.
Again, I have no idea what your ambitions are or if this would suit your theme. This is just what I have picked up from observing the more successful users of my podcast recording service. Shameless plug, sorry :/
Anyway, if you and your co-hosts or guests aren't able to recording together in a studio, you might give the service a try. You can use the coupon code WELCOME for 20% off your first the months. If applied to an annual plan, the discount will apply for the entire year.
Good luck with it and let me know if I can help with anything other wise.