I've added 2 new cassette players to my collection-a Sanyo M-GR59 and a Sony WM-F2015.

Sanyo M-GR59


Has the old Sanyo logo-and interestingly only has a fast foward button but not a rewind button.
Sony WM-F2015:

According to the service manual for the WM-F2015, it appears to be based on the WM-AF23/BF23.

Also, I looked at the WM-F2015's main circuit board and it says "WM-BF23"-so it must have been based on the WM-BF23.