Out of all the cars that I've seen El Camino'd, this is a first. For some reason the cheeky little British sports car from Morris Garage have been spared the ignominy of having the tail cutoff -- probably because convertibles are already roofless and removing the trunk top is strange to say the least. Anyway, find this 1971 MG MGB offered for $35,000 in Palm Desert, CA via Hemmings.
The most common style of cars to be subjected to El Caminoization is a coupe or hatchback -- quick work with a sawzall and a piece of rear glass gives you a small bed where the old trunk/rear-seats used to be, but removing the trunk from a convertible is a new one on me.
The astronomical asking price is somewhat justified by the super clean B-series inline-4 under the hood, but still this car should come with a $30k savings bond under that tonneau cover to be a really good deal if you ask me.
See a better car for hauling around British car parts? email@example.com