Sony NEX-5n with fast zooms ideas

Hi all,

Begin story:

Typically when I can't find a solution to a problem myself, I start to search for good reputable forums for external advice, and DPreview seemed to be a great start. This is my first post. I've lurked as much as I can stomach, so now I've joined DPreivew in hopes to get an answer from the experts.
I just bought a NEX-5n, and I'm in love. I had a Canon 60D and loved it too, but for certain reasons, decided to sell all of my Canon gear and switch over to the NEX-5n. I didn't like the Sony E-Mount lenses at all, and have always wanted to dabble in the oldies-but-goodies lenses such as the Canon FD, so I decided to buy a Fotodiox adapter to do just this. I'm now a proud and excited owner of the 5n, adapter, and Canon FD 28mm, 50mm, and 100mm. In my opinion, which some may consider seasoned and somewhat professional, this is a very awesome gear combination...

While I love taking photos, and fully intend to use this setup to take great pictures, I also intend to use this gear to record video...I'm a seasoned broadcast videographer who has shot, edited and produced tv commercials and shows, and can see the value in using these modern cameras for video production as well.
Okay, sorry for the story, but here's my big question!
Is there a zoom lens out there that has a constant aperture? I love the Canon FD lenses with the manual iris rings, and would actually prefer this! I just can't find a wide zoom lens with manual iris control. I don't care what age the lens is, I just want a lens that has a constant aperture, a wide zoom or super zoom, and the ability to adjust the iris possibly on-the-fly.
I can deal with the fixed focal lenses that I have now, and if there is no solution to my inquiries, so be it. I'm fine with any brand of lens as well...
Thanks for your help all!
Ryan~