The idea for this came to me last night, but like so many of my ideas it turned out to be one many had had before and had done a lot more with than I imagined. There are several older threads discussing how to use the front end of a BMX bike as a BC wheel with handlebars, an “unbike” as it’s called, including here, here, and here.
Here’s a video featuring it that I found and thought was clever and fun:
The rider seems to be a pretty good freestyle unicyclist as well as a BMX rider.