Hi Bob
I have just done a translation, and it looks like it's a one-off, perhaps they used a Mochette as a base?
IFA - KEY-FIELD 126 Unique piece /Unikat Year of construction 1961-63 GDR experimental construction Drivingready restoration needily As advertising media/eyecatcher or for old timer friends For further inquiries gladly under 01723145716 8.00-18.00 o'clock inspections desired, vehicle does not stand for payment in the north of Berlin a dispatch - during collection