Zoom Camera Lens

Is the lens you put on a DSLR the only thing that determines the optical zoom or can the just camera body contribute to the zoom it has?

I am looking to buy a digital camera with an internal zoom (lens doesn’t move out of the camera body). Any good suggestions?

I am looking for a digital camera that has the following features:
1. must have internal zoom (lens doesn’t move out of the camera body)
2. must use standard AA or AAA batteries
3. must be a brand name
4. must take at least 4MP pictures
5. would prefer one that uses SD cards
I am having bad luck with my [...]

My father passed away a few years ago and I was digging through some of his belongings and found one of his old SLR cameras that he bought in the mid-80s and it has a nice zoom lens with it. I have some pictures of it here.
http://www.jimmypark.com/tmp/bell_howell.jpg
I am thinking of buying a Canon 30D [...]