I agree with the OP. Why wouldn't they officially release these on one of their two official websites? (Yes Kanger has two websites) And when in the blue hell are they going to release Titanium or the controversial TC Nichrome coils?
Vapor Authority is the only site I've found that sells these and they sell them by singles. Also what is pictured above on the Vapor Authority website aren't the newer and improved V.2 SSOCC's with the fatter body and bigger juice holes. The ones at least in the picture here are definitely version ones and not version 2's (the ones that actually come with the toptank kit.
Over at sweet-vapes.com they are actually trying to get rid of these older, more slender V.1 coils at a reduced price while they offer the newer version 2's for about 3 bucks more. No SS at SV either though.
Your link: "Sorry, this product is currently unavailable."
Also, those look different than the ones included with the Toptank. My 316SS coil has a wider body like this:
Yep those are the newer and fatter Version 2 SSOCC's. The ones pictured at Vaping Authority appear to be the more slender Version 1's. I really don't notice too much of a difference though.