I phoned Velocity yesterday due to the upcoming need for some 650B rims. I remembered a few months ago the mention of the Dyad rim to be produced in a 650b/584iso. Indeed it is true, but with all good news comes stipulations. With a 24mm width and machined sidewalls, the Dyad is a proven touring and tandem rim as a 700c, yet in a 650B I'm sure it will see offroad use with the multitude of tire hitting the market. Alas, your local bike shop will only be able to procure these rims from Quality Bicycle Products. Velocity will not be selling them direct to shops or smaller, custom frame and wheel builders. QBP has them locked in, for 2009 anyways. Their Handspun wheel building program can build onto any combination of hub, rim and spoke of the users choosing.
The Velocity Dyad. Machined Sidewalls, available only in silver for the time being.