The Aiptek pencams are 1.3 megapixels which might not be enough; also, the lens isn't great and can distort the image a bit around the edges. Aiptek also makes a digital video camera, the DV2, but I'm not sure what the quality is like.
Transmitting the video probably won't help the quality much; you could use that to help you point the cameras. http://www.blackwidowav.com/ sells cameras and transmitters. Some of their stuff looks pretty good. Keep in mind though that for a lot of video transmitters (especially higher-power ones) you will need an amateur radio license, which cannot legally be used for anything commercial. I'm not sure what kind of transmitters you can use for commercial stuff.