If anyone's interested in a replacement for the aging leather cases of old TLRs, I found something which may be able to fill a similar role.
The internal dimensions are about 4x4x6 inches, just slightly more than what an Autocord needs. The TLR's own straps could fit through the dual zippers if desired, making it unnecessary to have a strap for the bag itself. There's a snap at the top so the bag can be closed without fully zipping. You could have a carabiner attached to the bag, quickly unzip the bag from your TLR, clip it to your belt loop and start taking shots.
Here is a link to the product. I have no financial ties with them. It can be found more cheaply through other sellers.
www.lowepro.com

The internal dimensions are about 4x4x6 inches, just slightly more than what an Autocord needs. The TLR's own straps could fit through the dual zippers if desired, making it unnecessary to have a strap for the bag itself. There's a snap at the top so the bag can be closed without fully zipping. You could have a carabiner attached to the bag, quickly unzip the bag from your TLR, clip it to your belt loop and start taking shots.

Here is a link to the product. I have no financial ties with them. It can be found more cheaply through other sellers.

ProTactic Lens Exchange 100 AW
ProTactic modular accessory bag designed to provide versatile storage space for photo and video gear. Front zippered pocket provides convenient storage space for lens or body caps and other accessories.