I don't have them but Mike Hansen at Dultmier mentioned them at the early bird session at the ICA show last year. i think there may be a picture of one near the end of the last SSCWN.
My bill changers currently don't have covers on them. I am trying to stop a nagging problem of water and crud stopping the acceptance of bills. I was hoping that if there are some out there that they could be retro-fitted to do the job.