Weird, I was just going to post the same thing...
I'm sure someone out there has fitted one to a K5
EDIT: Gazza, I've just had a look through the 2006 demon tweeks catalogue, found the following (which for some reason doesn't appear on thir website):
Pyramid Huggers
SV650S 04-05 in Black: £74.99 - part no. 07033B
SV650S 04-05 in Carbon: £119.99 - part no. 07032A
Huggers for the K3 are listed separately, but then I found this:
Powerbronze Huggers
SV650 '05 in Black / Carbon from £69.00 - part no. HSU22
The k3 & k4 are listed as the same part number though, so it looks like they can't decide whether a k4 is the same as a k3 or a k5