Zach,
This will be pretty intense to do with Marketo. Since Marketo is "lead-centric", you will probably need to have some sort of a relationship field between properties and leads that would need to be updated constantly and then fed to Marketo and used as a token for email.
Unless you have significant development resources, I think you will find this to be pretty difficult. I'd love to see some other community members take a shot though 🙂
If you do decide to go to an outside firm, our company (The Pedowitz Group) handles difficult technical integrations and would be happy to scope out the project for you. Feel free to email me directly at jason@pedowitzgroup.com if you'd like to discuss.