We are off to Kyushu and Western Honshu in about 4 weeks.

What is the latest on train passes that can be used from Yamaguchi through to Kyoto.

We were lucky enough to get a special on a JR East pass in 2010 and it was fantastic.

We're not travelling by train enough to warrant a normal JR pass - what we'd like is something we can use on non-consecutive days on Shinkansens and Limited Express trains... possible? or are we dreaming?

Is this what you're after: http://www.japan-guide.com/e/e2361_04.html
The JR West Rail Pass - Sanyo Area covers Osaka to Hakata (a little further than Yamaguchi).
It costs ¥20,000 for 4 days and ¥30,000 for 8 days. But non-consecutive days? That might be dreaming...

The following page from japan-guide describes how you can buy sets of multiple tix (4 to 6) and get a 5 to 10% discount.
http://www.japan-guide.com/e/e2359.html
I have not done this.

We might try the private ticket shops around stations next time and see what they come up with.....

There is a new pass due out in a couple of days that might help you although this one is also a consecutive day pass but you can take the nozomi's with this pass. I wish that they would've made it like their Hokkaido alternate day passes......maybe sometime soon.

http://www.japan-guide.com/e/e2361_07.html

Aloha!