Wanted - Collet stop for 2J collets

I have a pile of suppliers and am fairly good at net searching; but I just can't find one of these anywhere.
2J collets do not have an internal thread so it is not as simple as threading a plug.

These guys http://speedstopcolletstops.com/pages/1/index.htm seemed to be my best bet but they don't have this size.

Can anyone help before I spend too much time designing and building my own?

BTW - I do not run production so something like my link would be perfect.