Equity share in primary residence

[Justin Pumpr]

Hey all,

I'm wondering if anybody has ever invested in somebody else's primary residence? I'm not sure what the technical name for this is, but I'd describe it as a buyer doesn't have enough cash for a down-payment, so they find an investor who pays for the downpayment and gets an equity stake in the property,  but the property is paid for and owned by the person moving into the property. This would be similar to them buying a rental property,  except its much more passive. 

Is there a name for this and has anybody done it, or know any investors who would be interested in something like this?