Huh, I thought I was late tot he party, but it seems this ahs been going on all year.
I went ahead and just worked with what I could find at the local mom & pop hardware store, so it isn't quite up to code.
Currently I'm working with a Canon Rebel XTi. I intend to upgrade to a 5D MkII soon, so really this go around is just practice or a rough draft, really.
I got a 10" reflector lamp and 4"x6" vent reducer, as such my light source is smaller and I think I am deffinitly getting less light out of my flash for this smaller area. I still deffinitly get the effect I want, but it just isn't quite as powerful as it could be.
I chose to simply work with my Cactus wireless triggers, and while this bites me every once in a while it isn't so much that I'm particularly bothered. On top of that, I could always just wire them up.
I ended up with a lot less bending to do on my bar to connect my Sunpak Auto 383- just one right angle to make. I didn't like how my camera was only supported along one axis, so I added a cross bar flush with the flash bell to support the width of the camera as well.
I too got the problem of way too much light on the bottom half of the ring, where the flash was inserted. I simply added a layer of duct tape and that seems to have evened out the light quite nicely.
Lots of tape and a little elbow greese and I ended up with this.



And so far I've gotten results like this

And this
