Been looking for a USA bike [two wheels] to buy/ride/ship for this years trip over there, scanning many sites, these couple of interesting conversions were on Cycle Trader.

Kinda strange looking . 

Gotta ask why ?

I would say that the shifter knob is the reverse selector.

Don't need bike licence

Oh yeah, reverse, didn’t think of that. 

Why question ? the Co who are doing this are catering for small market for person's with disabilities, have found this out via a friend over there, this particular Co are base in Arizona. Not for everyone no doubt, but can get some back riding and continue there lifestyle and love of the HD. Equal opportunity which is alive and well with these conversions. Do need a MC endorsed licence to ride also. 

I'm not sure why someone who is disabled couldn't ride a trike?

I was thinking disabled rider too but noticed the bikes have, hand throttle and clutch and foot brake and gears so those four extremities need to function. One of my mates who lost a leg still rode a modified VRod so a trike would be a doddle and potentially have greater resale, but hey, maybe the point is just having something different, a lot of us are guilty of that. 

If the shift knob you are referring to is the one on the right hand side, it is for reverse. it's a fairly common conversion you can put on most Harley.