One of the eternal profundities of video these days is to shoot 16:9 or 4:3. Down here for commercial release you'd better be shooting 16:9 or it's hard to make a sale. But a lot of the corporates still what 4:3, well maybe for now until they wake up a bit more.
Now with SD cameras no matter which format you shoot to go the other way you're going to take a quality hit and have potential framing problems if you're going from 16:9 to 4:3.
Well from what I can see if you shoot HDV you've got all the bases covered, for 16:9 you can simply downscale and job done. But better still you can crop to 4:3 and then downscale and still not take a quality hit and you can pan within the frame so even framing issues aren't that tight.
Bob.