In our experience as a Cervelo dealer, Cervelo does not know what they're talking about in regards to adapting their own BBright system.
BBright is a BB30 shell that is 11mm longer on the non drive side. The cranks made for it are BB30 cranks with a longer spindle and flatter NDS crank arm.
Since the right side is BB30 width and the left side is outboard bearing width, an adapter is certainly possible for 24mm spindle outboard bearing cranks. But despite repeated calls to Cervelo and Q (who they claim have these parts), there aren't any adapter cups that do the job.
So when we need to install long crank arms that aren't available in BBright, we take a normal nylon Shimano to BB30 adapter from Wheels Manufacturing and turn the left cup down to almost nothing on the lathe. This is how they start:
And this is what the NDS cup looks like (this one is actually still a little thick:
The problem is that no one makes an adapter of this type for Campy, so you can't turn one down.
What they do make is adapters that replace the bearing with a cup that accepts the Campy bearing. BB86:
BB30:
Campy makes these for BB30 and BB86, but the BBright NDS is actually 45mm from centerline (
http://www.bbright.net/bbrightdrawings.pdf), so the 86 adapter is 2mm too wide. Trek's BB90 Ultratorque adapters are also 45mm from centerline on the NDS, but use a 37mm outside diameter rather than the BB30 and BB86 41mm OD, so they won't press into the frame.
Upshot:
Your best bet is to try a Campy BB30 adapter on the Drive side with a Campy BB86 adapter on the NDS. The problem is that the BB86 adapter is going to stick out 2mm further than it should (because it is designed for a 43mm centerline, not 45), so you'll have to find a way of reducing the total spindle spacers by 2mm.
If that's possible, it should work. If there aren't 2mm of spacers to get rid of, maybe a machinist can somehow reduce one or both of the adapter cups by a total of 2mm. If some of that comes off the DS, make sure you maintain enough chainring clearance.
Otherwise, have a metal ring lathe turned that goes between the Trek BB90 Campy adapter and the BBright bearing shell, then use the Campy BB30 on the DS. I would red Loctite this ring to the adapter cups so you can press it out of the frame someday. BB90 is very different than BB30 and BB86, so I have my doubts how well this would work. I haven't been able to find blueprints for BB90 to see how bad it would be, but the ring would be 2mm at the thickest (37mm to 41mm).
I hope that all made sense. Ask if I need to clarify.