I'm glad you brought this subject up. I really hate seeing big makers marks in the middle of the item.
I go to a lot of gunshows where people are selling holsters. Even on plain holsters the big honking mark is right on the front.
I would never buy one. Leather holsters are expensive (relatively speaking). I am not going to pay a lot of money to advertise for the person selling it. I'm sure I'm not the only one that feels that way. There is a nice spot on the backside of the holster where that could have gone and not distract from the holster itself. Now on smaller items like the spur straps you mention, I have no problem with a small mark on the buckle piece. On belts, up near the buckle look is a spot that is not gaudy. If fact, it might even be covered by a trophy buckle. The bottom line - I can see the need for brand recognition, and I can see that you will be proud of the item you made, but somewhere where it is a bit inconspictuous (sp?) is a good spot. Look at it this way: when you buy a nice table the maker didn't put his big gaudy mark on the table top did he? It is usually on the bottom, or it is in the drawer of furniture items. As a woodturner, the signature is always on the bottom of the bowl.
You see this in most crafts. That's my 2 cents, but at today's prices it's only worth half that much. cheers!