If I remember my Amiga trivia facts correctly - from the original ads and reviews in 1989 Amiga magazines - those slots did take a special GVP ZorroII Card shaped to fit the sloping GVP SERIES II A500-HD+ and 030 Accellerator cases!
Remember that the A500 LH expansion connector (and the A1000 RH expansion connector) is a ZorroI connector with 86 of the ZorroII 100 pins.
The A2000 uses a 86 pin slot for CPU Accellerators.
Comparison of the 86 PIN EDGE CONNECTOR on A500/A1000/A2000/A2000B models Zorro II/III Pins-EDIT-
Had a look through a few AMIGA WORLD issues....(Pg 7 usually has a GVP ad).
In the March 1991 issue:
' Unique new "Mini-Slot" brings out all the A500 expansion bus signals, allowing for exciting future expansion options - the only intelligent alternative to risky "Pass-Through" functionality. '
