Ok, I have updated and re-opened the run list to see if there are any other members who want holster assemblies before I move on to other projects. If so, let me know so I can make sure I purchase enough leather this upcoming weekend for those interested .
Eco-Flo is the brand of stains I use, and they do have a black stain. However, keep in mind it will not be like a "painted" black that is solid, but more like a slightly diluted black because it is a stain and not a paint. They do make paints for leather applications but I have never used them. If you didn't want to go the stain route, I could always make you an unstained holster assembly and let you attempt the paints.
If I had to choose, I'd probably use the Stain and Finish in order to maintain the natural appearance of leather, and any scratch weathering would probably look pretty cool. The paint would be best if you wanted a painted looking surface, however, I don't know how resistant to cracking it would be on sufaces like the straps that see a lot of movement on my holster assemblies.