I'm looking to get a detachable sissy for the missus when she gets on the bike. I have a 2-up seat so I just want to be able to attach and detach the bar quickly enough.

 i have a qd bar/rack combo from HD that works well,style is similar to the cobra one you linked,medium height with a pad,wife reckons its good and holds a roll bag well.

I have the HD unit with the gear rack, pretty good. Is quick release.

Any links gents?

In all honesty the Harley one is pretty good.  I had one on my Sporty and with the quick release tabs you could remove it in 5 seconds and put it back on in about the same time.  They are never cheap (and do not forget the back rest pad as well) but for a pillion they are the bees knees.  

I have one of these as well. I swap it for a top box bolted to a HD bracket when I need one. It's very easy to remove and replace and is very secure when fitted.

gidday mate you didnt say what model dyna you had but the cobra product looks like it is for a sportster.maybe check this one out https://www.jpcycles.com/product/903-657/cobra-black-quick-detachable-14-round-bar-sissy-bar-with-backrest it is the same price. i have a 2014 street bob and getting a sissy bar hooked up to it with docking hardware was a fucking nightmare. you cannot get 4 wires through the docking hardware so you have to run wires under the guard and that looks like shit. anyway i have had my say on this site before about that so enough said. having said that if only this product was around at the time i bought my bike the docking hardware looks like it bolts on above the indicator therefore you dont have to put wires through docking hardware leaving you a nice clean look when the bar is off. you should grab the luggage rack while your there they come in handy. if i can offload mine i will look at one myself. hope this helps. cheers

Cheers boys. 

I prefer to run my Streetbob as a solo seat so I purchased the Genuine Harley Detachable Sissy bar. 

Where are your turn signals? front/rear?