Almost a year since starting this thread and still no S&W 9mm carbine,
In that time seems the Colt 9mm flat top carbines have dropped a bit and can be found just under $1000 ,

Checked PSA's website today and while their 9mm upper lower Glock mag carbine kits can be had for around $550 ish seems all the Colt mag compatible lower units are sold out.

Still on my hit list but if S&W is listening still interested in a Sport II in 9mm