First of all, Brian, many thanks for taking the time and effort to create and upload the video. I am sure it will help a lot of people on the forum who either want to know how to produce HDR and even more who will be able to use it in order to improve their images by layer masking etc. Awesome work!
As you probably know, I have moved away from using Photomatix and now use Lightroom 3 with the Enfuse plugin. A couple of points about this may interest you and others who use LR3...
Whereas you exported the different exposure to Photomatix as JPEG files from Aperture, LR3 will export directly to Enfuse (or Photomatix if you have that as well) as TIFF files which, although large, do contain more image information than JPEG files, I believe? Not sure how much difference it makes compared to your results...
I had a go at the images you posted and used Enfuse to merge the exposures as shown below. I have never changed any of the Enfuse configurations as I find them to be great 'as they are'. I kept consistently getting some strange results in Photomatix and some may prefer the 'Enfuse' look over the 'Photomatix' look

Once Enfuse has merged the images it is automatically re-imported into LR3 where I will generally do a little bit of work on lens correction, the clarity, contrast, and vibrance of the HDR (I tend to also do simple spot-healing if needed). Anything more radical I will use layers for in CS5 using largely the same techniques as you so clearly enunciated.

My resulting shot is below.
I hope you don't mind this reply to your post - I am in no way trying to hijack your excellent post or detract from the great effort that you have put in. I am just pointing out another couple of options for those who do not use Aperture or PSE...
Once again, terrific work - thank you!!

My result