building an addition... by adding a mobile home?

[Eric Mcginn]

first some background:

I'm buy a property with two duplex, one of them has structural damage and I am going to tear it down. I have grandfathered zoning to allow for be to maintain my 4 unit status be rebuilding. I've been finding that having two serrate duplexes on the same property complicates financing, so I'm considering putting an addition to the good duplex to make it a fourplex. 

Can I put on an addition by laying down a foundation, rolling in a mobile home, and permanently installing it with perhaps a carport or deck connecting the two structures effectively "combining" them. 

is this just crazy?