The kayfun 3.1 has been discontinued on cloud9 too. I read the kayfun4 should be out soon. (Easter - Summer time) It was just a comment made on the semovar vs provari thread.
Apparently someone emailed cloud9 about restocking the 3.1(wanted it for the hybrid adapter on the semover) and they said the kayfun4 SHOULD be compatible but could give no further information....
I'm just repeating what I read (a few weeks back) just check through the thread, I can't find the email reference but it's mention again on page 85, guess you could PM the poster.
Maybe the emailer will see this post and jump in?
just to add I think the spare parts were still stocked last time I looked.