You are welcome, and at least maybe it will give you a start. There has been quite a bit of discussion over the years about a Joomla! Open-realty component, but nothing ever came of it.
I think that possibly the Open-Realty developer's hybrid license may have something to do with that. The newest incarnation of that license leave the program as "Open Source", but has certain usage restrictions that, IMO, keep it free being truly "free" software (meaning "free as in freedom, not free as in free beer). 
--rlparker