Adult tandem trike conversion I'd like to take my old tandem and make it a trike with dally tires and rims on the rear. Has anyone done it. Thanks
There is a front-end trike conversion system called the Newton that has been used for tandems. I have no direct experience with it.

There are a number of rear-end trike conversion systems that are all similar in design: the Trykit and Longstaff. I know that Longstaff has built tandem trikes from the ground up, although I don't know if their conversion kit is suitable for tandems.

You may note that these companies are all in the UK. Triking is much more established there.