I think what the industry is going to be flooded with in the coming month is either bullpup conversion (like the example in the OP), or projects/products several companies have had on the back shelf for years. I think what we're seeing here is either "early band wagoners" or companies who are hoping Kel-Tec takes the proverbial bullet on this idea-if it fails, only Kel-Tec has taken the brunt of it.
I'd put money on (at some point) someone drawing a line between the KSG and the HS-10 to the extent of "it didn't work then, it won't work now". According to many things I've read, the HS-10 was problematic and prone to failure. Dollars to Pesos that ONE FARKING FAILURE will doom this innovative shotgun in the eyes of many bleeding traditionalists.