I had one of the passenger backrests from HAC and ended up selling it, because the wife wasn't riding very often, now that she has finished nursing school, she has more time to go on longer rides.
I have done some searching and have found these passenger backrests, but not sure which one (your better halves found to like the most)
Cobra Mini - (wondered if i bought this backrest, if I could put a taller rest in place of the mini)
I got an OEM as well, fits and looks great. Ebay $53 shipped. Listed as a Vulcan rest, but the guy said he had it on his MS in the description. I don't ever use it for 2up, just to hold my T-bag.
Both will accept the optional luggage rack and I used the shorter one on my Marauder prior to adding a trunk. It looked great and the wife liked it as well.
Get a Corbin seat. Driver and Passenger Backrest and you can add what they call the glove box to the back of it. It’s a really comfortable seat. Stock isn’t great and the Mustang is no better. So win win with the Corbin.
I like the Mustang seat. When I rode for 5-6 hours on a stock seat, my tailbone really let me know how unhappy it was on a stocker. I picked up a Mustang on ebay used and to me, it was night and day difference. I am 6'6" and it feels that the Mustang pushes me forward slightly, because of the design. I have heard from shorter riders that they move backwards, so I think it depends on your height.
I find the mustang seat moves you forward too. I love to use my stock when I solo ride and the mustang for 2up I might do 3" forward controls this winter just got the bike.
In another thread you can see where I converted a Vulcan 1500 Classic seat to fit the mean streak. Night and day over the comfort of the stock seat, but it moved me forward about 2 inches. Moved enough that my knees start to get stiff when riding. I am looking into forward controls as well.