I used such a rig (flash bounced off umbrella mounted on bracket attached to camera). Now I just use this:
It is much more convenient and does a nice job. You can rotate the dome to bound of ceiling or walls or even off the wall behind you. Nice.
Haven't seen that one before.
What about the Metz - mecablitz 76 MZ-5 Digital Handle Mount Flash.? Does anyone use these?
Guide No 249'/76 m at 105mm!?! Sun in a stick is what that is! That is a flash!
Maybe you just need a different diffuser?
Have have been using a Gary Fong Lightsphere Collapsible lately and also use the ProMax System from Lumiquest and the Orbits ring flash diffusion devices. I mainly bounce between the Lightsphere and the Lumiquest. I have set the Orbits on an old SB600 remotely firing as a background fill light and it does fairly well.
A couple of weeks ago I shot at a conference in a hotel where I was stuck in the back 1/3 of the room shooting speaker's photos in a dimly lit room with 25-40ft ceilings. A couple complained about the bare flash on my Sb900 so I used the Lightsphere from about 50-70 feet away with a 70-200 the whole time. (Another reason why I like DX.) It actually filled in the shadows on the faces from that far away. Granted the ISOs where around 500-2000, but it was a pinch, and it pulled it off. I had a lot of down time and was able to play in empty rooms - and you can get some really good things out of it with the top off and bouncing it all over. I did add a note-card in the backside of it to push more forward though.
That said, I prefer the Lumiquest for the light and that it packs really small - I really liked the large one (big bounce) but that fell out of the bag somewhere. I like the Lightsphere where it will get banged a bunch as it really holds on tight and can collapse easily and it seems I can get more light out of it if needed.
Just a couple of thoughts - not sure if it helps.