The answer is YES wireless technologies work.
I work for a distributor of wireless communications equipment and we have equipment deployed all aorund the world for supporting wireless surveillance applications. Governments and Militaries rely on these technologies and I don't think they would be using something that does not work.
However do not use equipment on 802.11 protocol or in the 2.4 GHz spectrum. 2.4 GHz is the most congested frequency out there (with portable phones to wireless routers running on the same frequency it is not uncommon to experience interference).
My suggestion would be to use a point to multipoint configuration in the 5.4 or 5.8 GHz spectrum employing one base station or "AP" with subcriber units for each camera.
PLEASE DON'T USE UBIQUITI (you will not have a good wireless experience), it is a decent product at a good price but it is not very secure, not ruggedized and I have had numerous customers coming my way looking to change out there whole network of Ubiquiti due to its poor performance/security.
When it comes to bandwidth it all depends on the capacity needs of the cameras and the distance that each subscriber is away form the AP.
I suggest checking out Redline Communications(http://www.redlinecommunications.com/). They are a Canadian based company with alot of experience with the application of video surveillance. We have shipped thousands of their radios to Mexico City where they support the police departments city wide surveillance network. Also if you are looking for a product that is a bit cheaper and still performs well check out Airaya (http://www.airaya.com/), they are an American company with a ton of experience in surveillance.
PS. please don't judge wireless technologies based on bad experiences with garbage equipment. Use the good stuff.
You mentioned that you have the camera's set up in your office. Do you have a wireless router or a portable phone? If so you could be getting interference from these, turn them off and try again.
My company also has sales reps out in Calgary, if you would like me to hook you up with one of them let me know.
Regards, Jordan.