Camcorder sensors are smaller, so it's easier to make zoom lenses with reasonable image quality over the image sensor area.
There are 10x optical zoom digital cameras out now, like the [link|http://consumer.usa.canon.com/ir/controller?act=ModelDetailAct&fcategoryid=144&modelid=9824&sa=true|Canon S1 IS]. It's just a 3.2 MP camera though. Lenses get bigger and more expensive as the zoom increases and the sensor area increases.
If you really want it, Canon would be happy to sell you a [link|http://consumer.usa.canon.com/ir/controller?act=ModelDetailAct&fcategoryid=139&modelid=10598|16.7 MP Digital EOS 1Ds Mark II] that will take SLR lenses. It is $8k. !
[link|http://groups.google.com/groups?hl=en&lr=&safe=off&th=122a4aec9547c5a2&seekm=11783d36.0408170554.47f635a3%40posting.google.com#link1|This] thread talks about several issues in the digital versus film debate. It seems that we'll need about 40 MP cameras to start to beat good film.
Cheers,
Scott.