Here is a bracelet that can do with just about any vintage Seiko. I am not sure of the correct name, but I am calling it the Wide-Link Bracelet. It is hard to determine how many models were originally paired with this bracelet. So far my research includes:
6106-6439
6106-8569
6138-0011
6139-8001
6139-8002
6119-8450
6106-8569
4006-6020
4006-6021
4006-6027
4006-6002
6119-6400
...And PROBABLY MANY MORE
I have this available in 18mm and 19mm. It measures approximately 21mm at it's thickest point, and 16mm near the clasp. It is surprisingly light just as the original, but is solid link and not folded metal. It has 8 removable links and 6 holes for micro-adjustments.