Yaesu FT-891 is the latest equipment the japanese manufacturer is working on. Although the details are extremely limited, it seems we are talking about a HF/50MHz mobile radio similar with the FT-857 in size.
Update: Yaesu shows the FT-891 at Dayton 2016, seee the following link for more details: Yaesu FT-891 update
A test report suggests the Yaesu FT-891 has 30kHz to 56MHz receive coverage, with TX being enabled in the amateur radio bands.
We don't know exactly what type of architecture is used and it may very well be possible not to share the same design with the Yaesu FT-991 (as the FT-857 did with the FT-897).
Publishing as I get more info on it. Full Yaesu FT-891 test report can be found here.
Update: no, it's not April Fools, Yaesu applied for FCC certification.