In an article in the new RationalEdge,
Creating accessible applications with RUP, Gottfried Zimmerman and Greg Vanderheiden outline an integrated (into the IBM Rational Unified Process) approach for developing accessible software applications through use cases and personas that drive product development and dictate evaluation points for iterative testing.
The article in RationalEdge is interesting, even though the authors conclude that more research is needed to take full advantage of the proposed approach.