You'd be surprised how big some of it can be. Most programmes I've been involved with have used Sony PMW-400's and 500's and on occasion PMW-F5's. (even in tight spaces, like stagecoach buses) For news self shooting, journalists use the smaller PMW-200's.
Each broadcaster has their own standards, so the BBC tend to use Canon and Panasonic as do ITN. Lower end broadcasters utilise DSLR's, usually canon. (for example, made in cardiff)