sorry for replying once more to this interesting ride.
Just Paul Brodies cruiser with shaft drive came to my mind last night and I have to share this here too.
His result as shown at the North American Handmade Bicycle Show (2017, if I'm not mistaken): https://www.thespoken.cc/paul-brodies-shaft-drive-cruiser-3
The shaft drive system can be still ordered from a company called Sussex in Asia, at least the website is still up an running https://chainlessbike.cn/index_en.html
That is a whole lot of awful put together really well. If you block off the front half it looks kind of ok even with the unaltered shaft drive sticking the wheel out back. It is the front half that is not right. Maybe chunkier tyres would bring it together? I dunno. Maybe a horizontal top tube? Maybe both.