I got my Blue/Black Cab back in March. We live in Green Township near Anderson Ferry and Sidney. So far I've had the following sightings:
Mid May around 5:30 pm downtown - Bengal Red Cab circling around 5th and Main.
June - White Cab outside of the Biggs off Crookshank. Talked to the driver for awhile. Its his wife's Smart and they also live on the west side.
June - White Cab parked near Teak in Mount Adams
July 2nd - walking the dog on a culdesac off Linneman, noticed a Blue/Silver Cab in a driveway
Judging by my sightings I'd guess we have at least a dozen cars in town at this point.