DSLRs vs Prosumer Video Cameras vs RED

So, I'm in the beginning stages of a documentary, and the camera I have for shooting HD (A Sony HDR-HC7 HDV-based handycam) is looking pretty low quality compared to what's out there right now.

I have essentially three options within the budget we're looking at:

1) Prosumer video camera - The Panasonic HMC-150 is the closest form factor to my old DVX100, is around $3500, and uses SDHC cards, which are cheap. However, it also has a fixed lens, so shooting something from a distance is going to be a pain in the ass. There is also some chromatic aberration in the lens that becomes especially visible around dark objects in front of a very bright light source (like, say, tree trunks against the sky). The compression also has trouble with lots of random movement, such as turbulent streams up close.

I could go with a better HDV camera, which would give me the advantage of using cheap tapes instead of expensive memory cards, not needing a laptop or field recorder, etc. The image quality difference is fairly large at this point, though, and many TV stations today will simply not accept shows shot using HDV.

There are better prosumer cameras, such as the Sony EX3, but they are about twice as expensive, use much more expensive media, and still have highly compressed video (unless you buy/rent an expensive external recording device like the Nanoflash).

2) DSLR - The Canon 5D Mark II and 7D have created a whole new category in indie production by integrating HD video into high quality still cameras. The advantages they bring are lenses that are sharper, have much shallower depth of field (Which looks much more like film), and a very reasonable price (Around $1800 for the 7D, $3500 for the 5D Mark II, both with a zoom lens). Oh, and with lens adapters, you can use a wide variety of lenses (including cinema lenses). On paper and in some of the video clips shown around the internet, this would seem ideal. However, there are a few issues:

• The cameras have crappy on-board audio recording. You can plug in an external mic, but in order to get decent audio, you need an external mic preamp box which requires additional power; plus an unofficial firmware hack to disable the cameras automatic level adjustments. A much simpler (although possibly more expensive) way of dealing with this is to record audio with a portable audio recorder and use a clapper slate (or clapping your hands in front of the lens) to sync up with the image and/or crappy on-camera audio in post-production. Either way, a hassle.
• The video recorded is not the same size as the image sensor, and the process of squishing the image down to video size in the camera creates some problems, namely aliasing, which can get downright ugly. Aliasing is most visible with distinct lines next to each other, say in a truck's front grill or a striped t-shirt.
• The video is recorded in a highly compressed format that will lose a lot of detail in really dark areas, and can create some fairly visible compression artifacts if you're not careful.
• Due to either format limitations or EU regulations regarding a tax on video cameras, DSLRs do not record video clips larger than 4GB or longer than 10-11 mins, whichever comes first. This makes using a DSLR a lot like using a film camera, but sucks for documentaries where you could easily end up stopping the camera in the middle of a perfect moment that you cannot recreate.
• Speaking of documentaries, DSLRs are very difficult to get a stable image from while being hand-held, which means you need to get additional accessories (a shoulder mount, basically) in order to do proper handheld work... which costs an extra $800 at least.
• Each time a frame of video is recorded, it's not drawn all at once. Each line of the frame is recorded top to bottom in sequence. For relatively still images, this is fine, but when something moves rapidly through the frame (say, a car), it looks slanted. This is the "rolling shutter issue" or "jello", and if you ask me, it's fugly.
• The 5D Mark II, while having a larger sensor area and better low-light performance than the 7D, shoots in a non-standard framerate. There's supposedly a firmware update that fixes this - in 4-6 months.

Basically, these cameras were originally designed for photojournalists who wanted to also shoot some video, but in the same style that they shoot pictures - short, silent (or with unmixed audio) and not edited to a significant degree. If you can control what you're shooting, you can get gorgeous images. If not, you get image problems. Oh, did I mention the rolling shutter issue? Anyway, you get the idea...

3) RED Scarlet - Speaking of 4-6 month out, this camera seems on paper to be the answer to my concerns. Based around the same tech as the über-successful RED One, the Scarlet uses a vastly superior codec with much higher resolution, significantly more dynamic range, an next to no compression artifacts. The image captured is not downsampled like on the DSLR (at least, not by default), so aliasing is very little to none, and (if it's like the RED One) the rolling shutter issue is much less noticeable than on a DSLR. So what's the problem?

• You can get the Scarlet for $4750, but that's a fixed-lens design, so you can't swap the lens out like on a DSLR. Even if the built-in zoom lens is great, the sort of wildlife photography I'll likely be doing on this documentary will require a very long telephoto lens.
• The interchangeable-lens model is $2750, plus $950 per prime lens (or you can use DSLR lenses by using an adapter for $500 [either Canon or Nikon]), but you also have to buy the audio interface, batteries, etc. Oh, and if you want a proper viewfinder instead of a back-of-camera LCD display? $3200. Side handle for proper handheld shooting? $950.
• There has been exactly one 15-second clip of Scarlet footage shown so far (a close-up of an iguana on a soundstage), so it's impossible to judge what the final image quality will be like...yet.
• RED cameras are often back-ordered into the stone age, and pre-orders have yet to even start for the Scarlet, so good luck getting one this year.
• The image captured by the RED cameras is totally unprocessed (in terms of color and brightness adjustments, not compression), which gives you more options, but also makes it more work to deal with in post.
• RED cameras are not "shoot anything and it will look beautiful" cameras like mid-to-upper-end video cameras. For better or for worse, the RED needs a significant understanding of how images will look in post in order to shoot good-looking footage. When you have control over what you're shooting, this is fine. When you don't, you run a greater risk than other cameras of getting bland footage that no amount of post-processing can fix.

So, basically each of these options have significant drawbacks, and at least two of them are likely to be replaced with vastly superior models within a year. I will continue to do research, of course, but in the meantime it's a really tough decision.