Cost is a factor for all of us. And I am sure I am not unique when I say that it is entirely possible to use video gear outside of primary work to earn some money. You have the means, the opportunity, the good name, and the talent to use your video gear topside or even underwater for commercial interest, even if you just use it to finance your primary work.
Cameras like the Panny HVX or the PD170 (yes I know it's not HDV) are not appreciably larger. The L&M rig for the FX7 is a bit larger of course, but I don't know how small you need to get.
No one is saying that hard drives don't fail. Sure they do. But if my livelihood depends on it working, I am carrying a spare. The Panny going with the P2 is a nice choice. A bit limiting for capturing DVCProHD but unless you're finishing to film, that's generally not necessary. Solid state recording media is the future I think. Looking at what Panasonic is doing, Red, etc., I think this is the way to go. No moving parts, little to fail. I went tapeless in early 2007. The only time my projects see tape now is for archival purposes. And that is usually on fresh, full size DV tape. If I was doing short-form video, it could just as easily be mini-DV tapes.
All this belabors the point. The world if video is shifting quickly. The limits of HDV written to tape have been realized and lines are being drawn. HDV going to tape will quickly become the "entry level" system and support for advanced features will dwindle. AVCHD (h.264) written to solid state, or DVD based media will become the new standard and more sophisticated features will be available there.
It is absolutely ASTOUNDING to me what a $3k camera will do these days. You could actually shoot a REAL movie and not be embarrassed by it on a $3k camera. Things that were the sole domain of the CineAlta, and the Varicam 3 years ago, are now found in sub $10k cameras.
But I have a feeling that tape mechanisms in cameras are about to become as quaint as a bellows on a still camera. And it's not going to take long to happen.
Cost is a major factor... my work is largely as a non-profit fort educational purposes. There is little grant money available for scientific research in the marine environment (unless you're working for the Navy), much less for marine science education.
Were I doing this for high dollar clients, I would undoubtedly have a different set-up, although many of the "professional" camcorders and housings I've seen would have little value in capturing some of the footage I shoot because they are simply too large to get into the nooks and crannies.
Tape drives can fail, but if it is just the tape, I simply put a new one in. I've actually only had one tape drive mechanism "fail," and it was repaired easily with a simple turn of the screwdriver topside. Hard drives fail... and can you replace one in the field? I don't think so. If I'm on an extended trip to foreign dive destinations, I'd hate to have the hard drive fail and not be able to replace it myself with a spare.
It is also a matter of having hundreds and hundreds of hours of archival footage on tape that I can simply pop into any one of my mini-DV or HDV camcorders and recapture if necessary. Can't do that with a hard drive based system unless you have a separate camcorder with a tape drive.