Funny this post came up.  I just got off the phone with Impact Guns about 30 minutes ago;  my second S12 just arrived today.  :bangbang:      
    
Yea, I get on there occaisionally.  I saw where someone was offering a bolt on conversion now.  Haven't looked into it too much though.   
So far I'm thinking:   
S12 #1 = Folding Tromix stock, 8" barrel, Shark brake, maybe some HK-style or ghost ring sights, as well as whatever other magic Tromix can do.   
S12 #2 = Fixed Tromix stock, 12" barrel, Rem chokes, competition brake, and maybe a C-more or other red dot/reflex/holo sight.     
I need more $.