Here's the Gun Blogger .45 housed in a Blackhawk Serpa holster; click on the thumbnail for a bigger image.
Their holsters were quite interesting. Made of carbon fiber, if I remember. One model has a detent holding the gun; this one had both detent and a finger lever, engaged by the trigger finger, and which holds the front of the trigger guard. (I had problems with it because my fingers are too long, but the detent model worked nicely).
On the reverse side are three screws that hold the body of the holster to its belt connection. You can switch between standard belt and paddle configuration. You can also angle it straight, or up to about 45 degrees forward or back by adjusting the screws. Separate controls allow you to adjust for width of belt. All in all, a very nice holster!
UPDATE: the problem with long fingers is this: if I lay my finger in the usual position, just straight along the holster, its tip goes may 1/2" beyond the end of the latch. Thus I'm pushing, not with the last segment of my finger, which would do nicely, but really with the joint area between that and the middle segment of the finger. The joint has to flex backward a little to push it, which means exerting a fair amount of pressure, and the last finger segment pressing hard against the holster (not the lever). If the lever were just 1/2" lower it'd be perfect for me (and then probably too long for others).
I experimented with bending the finger a bit and using the tip, but found that sometimes the finger then went into the trigger guard. Maybe 5% of the time. That'd not be a problem with these double actions, but not something I'd care for with a single action.
BTW, the Serpa is otherwise excellent in these regards. The trigger area is blocked off by the holster while the gun is holstered, so you can't get your finger into the guard. The latch area has ridges on either side to guide your trigger finger and make sure it goes straight back and doesn't drop into the trigger guard when you draw. A very nice design, unless you have overly long digits (and pretty good even then).