I am curious about that logo. It looks to be a wings/staff/snakes in black, but the exact number of loops etc. is hard to discern from the small images.
There have been updates on the goggles front:
http://www.mortonsafety.com/index.aspx?Command=GroupInfo&GroupID=10875
And that same site has similar (if expensive) boots:
http://www.mortonsafety.com/index.aspx?Command=GroupInfo&GroupID=10729
For gloves, the following have been suggested:
http://store.weldersource.com/750.html
(Please note, I have not ordered from any of these places and do not necessarily endorse these vendors. These links are provided solely for informational purposes, and have been gathered from various sources on the drhorrible.net fan pages)
On the coat front, I've made an attempt...
http://img.photobucket.com/albums/v506/Lingarn/LN_Horrible1.jpg
Starting from Simplicity 5443, I cut the right front panel short about where it started to curve into the neckline. If you look carefully at the video, there is a several-inch extra flap between the front and back on the right side that is visible when Dr. H goes flying; this seems to be consistent with a several-inch right panel that is hidden most of the time by the left panel.
I doubled the left front panel, added material to the shoulder region for the button-hole area. If I try for a closer version, I will add material to the entire side that buttons; the firefly shots show that there is a stitched strip running down the length of that side from the shoulder to at least the waist.
I sort of made-up the collar... It was late... Making it smaller (that is, smaller opening) would be better. I also altered the front pocket and back half-belt designs to be more in line with the source material.
Material is some sort of white cotton twill that was on sale. Goggles are not the ones posted above, but just something I put together from convenient parts. Safety goggles, paint, plastic from a chinese take-out box, and some mountain dew cans.
Overall conclusion is that if I can come sort of close, then an experienced tailor/seamstress should have no problem. There isn't anything really that hard in this costume, though my optimism hides my terrible craftsmanship.