I've been somewhat surprised that in the course of all of the talk about bags and US-made goods on various blogs, Arizona-based Custom Hide has somehow been overlooked.
While I have not had the good fortune of trying one of these bags out personally, they used to be the talk of the town on a particular men's clothing forum that I used to frequent, specifically the 1945 US Army Briefcase. From what I've read, though, they are very well made, use good leather, and offer a number of customization options on orders. Those options include several leather colors, the overall size on the bag, the number and placement of pockets, and the style and finish of the hardware used. And, as I mentioned earlier, they are made here in the US, but their prices are really quite reasonable (which is a lot more than can be said about some other companies/collaborations lately).
Here are just a few bags that they offer:
US Army 1945 Briefcase (mentioned above)
Classic Leather Briefcase
Be sure to check out the website as it offers at least a dozen other styles, including a backpack and duffle bag. While they may not be breaking any ground in the style department, Custom Hide is making classic, well-made, leather bags for reasonable prices, and they come with a lifetime guarantee. If I was in the market for a leather briefcase, this would definitely be my first stop.
Also, be on the lookout for the A Trip Down South x Custom Hide briefcase (I wish it was true, but this is supposed to be tongue-in-cheek).