If the bike I towed that way, was an old bike with a chain I could take off and a bike that I didn't LOVE like I do my Harleys (2) I might consider it.
NOW not knowing what You want to pull? ME,
I like a covered trailer when putting to tow and maybe I'm spoiled as I build my own trailers.
I have a single light weight covered trailer now /ramp door, that holds ONE bike as that is all I can ride at one time... locked and harley out of sight.
The dolly system or front off the ground, has been used for a long time, and some one or company re-invents it every once in a while.
I prefer to trailer Pack mine and in no way OPEN behind my rig.
I have made a few similar devices you mention here for a couple of customers years ago for their dirt bikes but never wanted to try one for mine..
To tow legal, you would have to have a light set-up and you would get lots of dirt let alone miles on bikes rear tire and saying nothing about the harleys don't lubricate properly in neutral being pulled that way. And what about the belt n bearings.
A poor way to haul a harley unless you can Ride on it while being towed, an Yell a Yahoo every now and than... Now that I Like!
Call me old fashioned and set in my ways.....
signed....BUBBIE