Hi
Ray - There's two styles and brands of holsters I wear that you may be referring to. The one below is from El Paso Saddlery, and is their Mdl 77 or Tortilla. I've got many of these for my S&W revolvers, pancake style, concealable, but also great for the field, as they can be worn high-ride style, out of the way, and afford a quick draw/easy access to the handgun. They work well for getting in and out of your truck, and are comfortable when driving as they tuck right into the body. This is the model I suggested above to
Squatting Wolf, and shows my 3" M29 Classic. They also make it for your 4" M629.
El Paso Mdl 77/Tortilla shown below with a K-Frame S&W Mdl 617 4", 10-shot 22LR. This a shot taken near Havre, Montana when I was popping prairie dogs at the mid-840 yard mark using my custom Holland 243 Ackley Improved.
The rig shown below is from Galco, called their SOB (Small Of Back). They make it for both autos and revolvers. I like this one as it's completely out of the way in the field, gives instant access to the handgun, and you hardly know it's there. Great for concealment also with a jacket or shirt tail to cover the weapon, but not the hot setup for driving as you can imagine. This style also allows for other things to be worn on your belt in the hip position.
This is the rig showing my Kimber Tactical 5" holstered, with the Kimber 22LR conversion unit aboard (great for shots of opportunity at Skippy for .45 familiarity). Eastern Oregon, having fun with squirrels and my 17 Mach IV (Sako Vixen L461/Shilen/McMillian w/Canjar single set trigger & Leupold 6.5-20X, shooting 25gr Bergers)
The Galco SOB shown is a two slot holster, ditto for the El Paso rig above. The three slot rigs give you the choice of different cant angles for the handgun. For all around use, field, driving, and concealment, the El Paso design, or pancake type is probably the best choice. Most good makers offer this style for good reason....very popular and practical.
Hope this helps your decision. Let us know what you come up with.
I knew you couldn't wait!!!! 
) and I really like some of the ones that El Paso Saddlery had so I'm thinking I'll go with one of them.
...maybe I should get both!
.......................Smart choice, it'll still be there when you're ready to pick it up, and you won't have a buggered up ride! 