Speedo Trip Knob

Ever since Ive had my 68 Barracuda, Ive been looking for the knob that works the trip meter in the speedo...Dash is coming out for a refurb soon...any ideas where I might source this part..Im an Aussie, not a lot of the rarer parts around here but I have scoured US ebay etc too
Thoughts?
I know I've seen it somewhere, I believe Classic Industries or Year One. It was $20 or so.