SIG has done what Glock should have done many years ago: partner with a firm like CAA and produce official branded carbine versions of their pistol line. The SIG P226 Carbine and SP 2022 Carbine as simply their respective pistol converted to a carbine with a CAA Pistol Carbine Kit.
Each carbine feature a side folding stock and plenty of picatinny rails.
These are almost certainly going to be limited to the European market.
On a side note, I have used a Glock in a CAA Carbine Kit and it was a joy to shoot. I will blog about it soon.
[ Many thanks to Gregor for emailing me the photos and info. ]