Use a Canon A610-640, A710,  or S3 IS with the new CHDK firmware add-on for it:
http://scratchpad.wikia.com/wiki/CHDK

Use any of the simple bracketing scripts available for CHDK then you can set as
many exposure bracket steps as you want for as many exposures as you want in JPG
and/or RAW. Set your exposure brackets by shutter-speed, aperture, or
flash-output.

Use this free utility to auto-align and crop all your images:
http://www.flickr.com/groups/hdr/discuss/72157594229411664/
(also handy for making animated GIFs from a sequence of still-frames)

Then use the "Connect Images" option in PhotoLine-32 from www.pl32.com
You can also use the RAW images as PL32's HDR "Connect Images" works in 16-bit
mode.

Better HDR images than any other cameras and software on the market.

If you get creative with this, then by using Helicon Focus you can also include
focus-bracketing steps (using CHDK scripts) for each exposure bracketing step to
get unparalleled depth of field in your HDR images too, resulting in ultra DOF
HDR macro-photography. For most of the CHDK enabled cameras you merely have to
turn on its own focus bracketing mode while running an exposure bracketing
script. Or vice-versa, run a focus-bracketing script while using the camera's
built-in exposure bracketing. But for ultimate control and bracketing steps
write a short script that does both, focus and exposure brackets, for you.

Since I'm interested only in retaining shadow
detail in daylight shots, maybe I could
get by with only two different exposures
and a post-processing algorithm of my
own design,  as opposed to
using off-the-shelf HDR software that
might need a wider range of exposures.
In this case a viable alternative to
using a bracketed sequence might
be to mount two identical (cheaper then SLR)
cameras on the same tripod. In my project
my subject trees are always far enough away
so parallax would not to be a problem. Then
I could two-handedly snap both shutters
simultaneously and get the exposures a
lot closer together than .7 second,
I bet.

--
Charles Packer
http://cpacker.org/whatnews
mailboxATcpacker.org

Actually I would forget about the bracketing feature. Few cameras do more
than 3 brackets. Some dSLR's do 5 (Pentax K10D being one). However, even
with 5 it is nice to have more images. What I suggest you do is use the
exposure compensation function on your camera. On my K10D I can set it for
1/3 steps. So I start at the darkest end of the exposure compensation take a
picture, then move up one step to the next one I do this until I have made
my way through to the brightest image using expsoure compensation. I get 12
shots this way and it works quite well.

=(8)

Oh, you will want to do this on a tripod or if you have Photoshop CS3 you
can load all of the images in to a multi-layered document and then use the
Align-Layers function. It will make the image aligns. Though I find it
faster to use a tripod.

=(8)