You can do that with any FireWire camcorder - well, certainly in iMovie HD 6 and previous ..I haven't tested that in iMovie '08.
Sony aren't really in direct competition with Apple, as Apple don't make camcorders ..and you may remember that the head honcho from Sony burst onto the stage during SJ's MacWorld address the other year (2005..?) and was introduced by Steve as he announced iMovie HD, because Sony was overwhelming happy that iMovie could import hi-def material from Sony's new hi-def Z1 and FX1 cameras. Apple and Sony worked together to ensure that iMovie could handle hi-def video shot with Sony camcorders.
But perhaps I'm not the best person to respond here, as I don't think much of hard disc camcorders; the compression's higher than with miniDV tape, a head crash can mean that you lose your entire discful of video, it's often more finicky to import ..the only time I use a hard disc for recording video is if I use a '
FireStore' piggy-backed onto a miniDV camcorder.
A computer with a spinning hard disc inside is a fragile thing to use as a monitor, if your rig has to be moved: it's only sensible if you're in one fixed spot while you're recording. If I'm shooting with the camcorder on the end of a pole, I just run a video-out cable from the camera to a mini monitor (..or even to video glasses!..) so that I can see what I'm shooting with the remote camera: drop your Mac and you're really in trouble!
To use your Mac as a monitor, you should also first calibrate the Mac's screen so that its colours and brightness ("gamma") match that of the camcorder, otherwise you might adjust the camera to match what you see on the Mac, and end up with over-exposure, or the wrong colours.
So maybe you might rethink
why you want to use your Mac as a monitor. And continuous capture to a Mac's internal disc while shooting may put too much strain on the system (..as the Mac will want to do various 'housekeeping' jobs while the video's coming in, such as indexing files, swapping memory to and from disc, etc). It may be better to capture to an
external disc ..which Canons don't like to do: they like to be the only FireWire device in the circuit. But as you want to capture to a hard disc camcorder, maybe capture straight onto the Mac isn't what you have in mind.
So, all in all, why not think again about what
exactly you want to do, and why. And Sonys work perfectly well with Macs, in my experience..
P.S: Any hi-def camcorder will need to have its video 'converted' during import into iMovie, as hi-def video is severely 'compressed' into a non-editable format, and it has to be uncompressed during import so that it can be edited. That's not just Sony camcorders; that's every type of hi-def. The conversion takes a lot of 'horse-power' during import, so shooting hi-def and simultaneously importing it in real time into iMovie can be difficult.
(..Maybe that's what you're trying to do, as you said "..I was astounded to find out that I was unable to record directly onto iMovie. Oh well. Further iMovie has to convert the file after it is downloaded from the camera's HD. I'm disappointed.." ..all hi-def has to be 'converted', standard-def miniDV tape doesn't, but standard-def AVCHD, as from a hard disc camcorder or a camcorder which records to internal memory chips or onto a miniDVD,
does need conversion during import..)