Might want to read one of these stories "Damn the regulations! Drones plying US skies without waiting for FAA rules" or "FAA Halts Man’s Drone Photography Business Over Regulations" before you run out and start investing in equipment.
EDIT: Remember crossing the line on this may have you trying to explain "violating the law" to your local Board of Registration. Not really worth the risk.
I have a neighbor down the street who has one of those helicopters that is radio controlled. It can fly probably 200 - 300 feet up and hover in position.
Now I have wondered how hard it would be to strap a digital camera with a timer every 30 seconds or so to go off. Can it take the type of photo necessary to make a photo-model? I mean, it probably isn't possible with an un-calibrated digital camera. But Panasonic came out with a mirrorless camera that may have the ability. I don't work in that field. But the concept is intriguing.
The rig for correctly mounting a digital camera to obtain results good enough for photogrammetric use would cost more than the UAV. Maintaining forward lap and side lap in an UAV would be virtually impossible. It's more than a camera and a lifting body.
Oh I'm sure that to maintain altitude and flight line alone would be be a daunting task. Much less pitch, yaw, and skew.
There is some interesting new technologies out there also that may someday be very useful. Like http://www.123dapp.com/catc h">Autodesk 123D Catch software. I can see this being used in a limited, small batch topographical format that would be completely doable in just a few years, if not sooner. It would just need to be properly scaled.