There will not be a semiauto version because it would probably be ruled a destructive device.
Although the AWB is dead in most states, the Streetsweeper et al is a destructive device under the Gun Control Act of 1968.
The Gun Control Act of 1968 said:
4) The term "destructive device" means--
...
(B) any type of weapon (other than a shotgun or a shotgun shell which
the Secretary finds is generally recognized as particularly suitable
for sporting purposes) by whatever name known which will, or which may
be readily converted to, expel a projectile by the action of an
explosive or other propellant, and which has any barrel with a bore of
more than one-half inch in diameter; and
So, in other words, any shotgun with a bore over .50 cal (read: anything shotgun bigger than a .410) that the Secretary finds "unsporting" is a DD.
Long story short, the Streetsweeper et al are DD's because they are considered "unsporting". The ruling said that they are non sporting because they are heavy and wide, have high capacity, a folding stock and two pistol grips,
look scary, and important for now, are more or less semiautomatic.
They aren't in the habit of declaring pump actions non sporting, but really, there's no reason they can't. We just have to hope they won't.