I bought one of these with my Cotton Carrier chest harness as well (no...just the camera harness, not the model) - http://www.cottoncarrier.com/carry-lite ... es-bundle/
I haven't used it a lot, but it does the job. The only down side is that when you sit down (like back in the car) it gets in the way.
There is a review online comparing the Cotton Carrier side holster to a different type called the Spider Holster. I can't find the direct comparison, but here's a review of the spider holster. http://www.photographybay.com/2009/10/2 ... on-review/
The issue with these sorts of carriers is that your camera is subject to being banged on stuff as you walk by.