Hi Anika,
I’m sure it’s possible to build that. I think it would be a pretty big deal, though.
Despite having built 30+ sites with MODx, when faced with a real estate situation I have opted for for dedicated Real Estate systems. At the risk of "un-selling" MODx for this, here’s my take...
Easy Realtor Pro looks nice, as it’s cheap and has loads of features. But I found bugs that I had to fix here and there. Tech support was OK, but spotty - mainly one guy, whose response to bugs wasn’t helpful - more like, just re-install.

It also runs pretty slow - probably somewhat clunky DB programming. Lots of generated HTML, so content isn’t separate from layout at all. It does work, but it’s decidedly funky.
"The Real Estate Script" was much more solid, and loads of features.
http://www.therealestatescript.com/
Yes, its structure is largely based on tables, but templating is still not too bad because the author did a really nice job of organizing the templates, and for tables, they’re pretty easy to apply CSS to if you’re good at it. Yes, it is possible to have tables that suck less than others.
Maybe someone will have a MODx-based solution.
Good luck, Dave