There certainly has not been any response from hub mfrs to produce 145mm hubs in the 28h category. Case in point, discussed in this 3 year old thread.

With all the deep section carbon rims on the market these days, you would think those mfrs could anticipate more hub requests for fewer counts than 32h. But, 28h hubs are still nonexistent.

As Ritterview stated in that old thread, Chris King sells maybe a handful of tandem hubs per year and spec'ing anything new is not a priority. That pretty much sums up the availablility and importance of niche products. 145mm is going nowhere, maybe even backward IMO (cite the demise of the WI Daisy rear hub as the last victim).