We've got quite a few success stories referenced on the SOA Resource Center. There are more in the works, but if you've ever worked on success stories before you'll know that writing them up is often difficult for a number of reasons, e.g., they can't be too technical and companies are often concerned about divulging internal secrets.
Anyway that's not the point of this posting: we're working on a couple of success stories that are based on our own internal use of the SOA Platform. Of course external readers will view these as slightly less important than "real" customers, but to be honest I think that's a bad thing. If anything they show our commitment to 'put our money where our mouth is'. In each case we've taken critical systems that have been running continuously for years based on competitor technologies and replaced them with our own products. It may seem like an obvious thing to do, but you'd be surprised how many companies don't do that. The feedback we've had from those development teams has been extremely positive and hopefully I'll be able to point at the relevant success story soon. Congratulations to everyone involved!