Jumping in on the whole "mods" argument...
Mods can indeed do anything. And they are free with the purchase of the PC version of the game. It is possible for a mod to do anything,so long as it's within the limits of the engine (and sometimes beyond,thanks to Script Extender utilities). In theory,a mod or mod collection could have made a Shivering Isles equivalent (Look up Nehrim: At Fate's Edge sometime) and are of varying quality. This DLC is interesting,and the big feature,that we know of,is already done by a well known mod. However,this DLC will more than likely include other features. However,since non-PC users can't use mods,they must used official DLC,so Hearth Fire,if it is only a "Build your own home" thing,will be able to scratch the itch of console gamers.
Also,I don't see anyone pointing our Oblivion's "themed home" DLC's...
More on topic,if this is legit,colour me intrigued. Something to keep an eye on.