Thanks for the suggestions.
I'm kind of worried that the Glif won't provide enough grip, so I've been looking at the Gary Fong iPhone 4 tripod adapter. Downside is I can't use my Otterbox case at the same time, but that would be okay for most shooting. I've also seen a ton of Glif ripoffs on Ebay and other sites, calling them Dot Lines, or something like that.
The Diff case is definitely cool looking, but I think overkill for what I'm wanting. I'm also not confident in mounts that are offset to one side, as it can possibly introduce bounce into the video, especially if mounted in/on a car.
I currently use an Otterbox Impact series case for my 4S, and I was wondering if that generic mount might fit with my case installed. I may be mounting the iPhone externally on a car, and want to keep the protective case on my phone to ward off random debris. The Diff looks protective enough, I'm just not personally comfortable with the offset mounting point.
Ohhh, what to do, what to do...