These days BMW's M division is pretty busy, cranking out all manner of sport-tuned models in every form. You can get an M3 as a coupe, convertible or sedan, the M5 in sedan or wagon form, and the M6 as either a coupe or a convertible, in addition to M versions of the Z4. But back in the late '80s, the selection of M cars was much more limited. Not that the engineers in the sporting division weren't trying, though. Case in point is this M5 cabrio prototype that almost made it into production, but was canceled at the last minute.
Starting with an E34-generation M5 sedan, engineers in Munich chopped off the roof, strengthened the chassis and replaced the four doors with two longer ones. (If you think the idea is entirely absurd, just look at the Audi A4 cabrio and its quattro GmbH-tuned versions.) The resulting M5 convertible prototype was actually scheduled to debut at the 1989 Geneva Motor Show and even priced at £50k for the British market, but fearing that its addition to the BMW line-up would create demand for a conventional 5-series convertible and subsequently harm sales of the existing 3-series cabrio, BMW executives decided to kill the project. Only one prototype of the M5 convertible was made bearing ZS license plates from the BMW Individual program, as you can see in the gallery below.
Related Gallery1989 BMW M5 convertible prototype