Thanks for the reply and detail. I haven't been on the actual hardware side of field in a very long time.
Any Dell or HP server tower will do, if you are unable to get those then an old desktop can be repurposed as a server running something like Ubuntu Server or CentOS. But since you are already planning to use a Pi for this you might be able to simply stick Raspbian on it.
Maybe someone can suggest whats the best route. I do know I want it to be linux based and written with Python preferably. ?
Are you looking for an
instant messaging server software?