Headbanger - lots of seat choices, both domestic and Japanese. Check out this forum. I bet if you search on seat you'll have plenty of reading material.
BTW - I stole that picture off Samurider's website. Takashi's site is a good place to start if you like the retro look. If you don't see what you want, ask him. Webike is another good Japanese resource.
Several on this forum, including me, picked up a K&H seat. Expensive and a 5-6 week wait to have one made, I don't think you'd regret a K&H as a choice. Mine has spoiled me rotten - 3 or more hours in the saddle and very little discomfort.