I recently purchased the following 62" bag through Dillon Precision, and am happy with it. It's padded, and has 3 internal hook-and-loop straps to secure your rifle. On the outside, it's got two pockets (they say 3, but two share the same space), plenty of loops, and pack straps. The pack straps can be tucked inside a hook-and-loop flap for snag-free dragging. Since the bag is padded all around, it could also be used as a makeshift mat - but to be honest, I only used it to sit on while glassing. I'm happy to lay in a mud puddle if I'm fixing to shoot a critter!
I hauled mine through mud, rain, and snow for a week on a recent hunting trip. The bag worked great. The only problem I had is it's not water-proof, and I didn't apply any repellent sprays or anything prior to the trip. On the bright side, I was able to fit drop charts, a range finder, spotting scope and tripod, weather station, binoculars, ammunition, rain gear, and a few other small items into the bag. All of my gear came out unscathed, which is all that really counts in my book.