TBR has featured bikes-on-bikes, but this is the first trike-on-trike that I've ever seen. It was completely his idea, but I was more than happy to make his dream a reality.
This may have been prompted by a four mile tour of errands that Ky did with me via Xtracycle + stoker bar. I ended up using a salvaged drop bar that was chopped just long enough for some bmx grips. It was Ky's first try with the stoker bar; he did well and had a blast.