The real estate professional is a busy person. This is not a career that lends itself to having (much less wanting) to haul around a lot of gear, yet it is leaning heavily in the direction of needing videography. The quality of footage you can shoot (in HD no less) with your iPhone is excellent, indeed.
But why not maximize it?
There are several options available to you, and when you consider the end results, very economical....
Owle Bubo has made some fine products that give stability to your shooting, help in rectifying ambient sound, and great lens accessories for both the 3rd and 4th gen iPhones. It may take a bit of searching online, but this product is well worth it.
The Phocus is an iPhone accessory that, like the Bubo, your phone slips into, it gives you that camera-held feel. It also hands you the wide angle effect from the lens, giving you that all-important pull-back effect....it is lighter than the Bubo, being made from plastic rather than metal, so it would be up to you to determine if that's a positive or a negative....
The Snapmount is an effective and cost-effective tool, the snap mount allows you to perch your iPhone, standard or landscape, on a tripod. You can fit lenses to it, and it's slim design allows for easy access to all the controls on your device.
The Olloclip lens is not a "surround your phone" option, but it's a 3-in-1 device that is updated all the way to the new iPhone 5s. It gives you a 10X multiplier for zooming, (the 4-in-1 gives you a 15X multiplier) a fisheye, and a wide angle for pulling back....A very versatile and up-to-the minute device accessory. If you want that "body of the camera" mount option to attach the lenses to, Olloclip does offer one for a low cost....
The Mobile device has rapidly become the agent's best friends in so many ways, and that HD camera it has on board is no exception to the built-in business tools it has. Sometimes a little accessorizing is a good thing, and the products above won't be something you have to concern yourself with as far as weight, bulk, or space occupation.