EFI Scan Builder a.k.a. Velocity Scan Builder 1.0 was my first XP-ish project. We did just about everything except automated acceptance tests. The success helped persuade the rest of my department to adopt XP.
Scan Builder 2.0 is in progress, and we are doing all XP practices, including automated acceptance tests, with some limitations on pair programming because the small size of our team.
The Scan Builder team is in the client appliations department at Electronics For Imaging, Inc.
-- KeithRay