Twinis (twin engined Minis for those of you who forgot) were made in a wide variety. John Cooper's version became famous after it almost killed the man himself, but there were many more. You may be surprised about the number of Twinis built on Mini based cars too, or ones that almost saw the light of day. From Deep Sanderson to Butterfield Musketeer and from Scamp to Ranger. Read more about some of them here.
Tim Neal tipped me off about a Twini that's offered for sale in New Zealand. According to the seller it was built in Dunedin by a man who made more Moke style cars, all road legal ones but just with the single engine. This one, however, was different and was never road registered. It is now offered for sale, still as a project and as a 1970 Mini.
Apart from the mechanicals not much of the Mini's base appears to have been used with home-made steel floors, or so it seems, and a body which looks to be made of aluminium. It comes with a 'condition unknown' 850cc engine at the rear and a 1000- or 1100cc that has to be mounted in the front subframe. There are twin fuel tanks and 12" wheels. A rewarding project no doubt. See the ad here.