I have a belt slide holster from Bob Mernickle. http://www.mernickleholsters.com/ps/ps18.html
It's pretty thick leather, nicely stitched; I've had it for several years and it's held up quite well with almost daily use during fall, winter and spring. Because it's a minimalist holster and lets the muzzle protrude out the bottom, it holds my Gov't Model or my Commander equally well, and there's no reason why it shouldn't work for a longslide. It even fits my P-35.
This is a great holster for concealment because it snugs real close. Of course, you need a cover garment (like a vest) to keep the exposed muzzle from showing.
Bob has lots of other holster designs, and his belts are super-heavyweight and topnotch.
