After much thinking about if I really wanted a top case, or simply to add a rear luggage rack, or just to stay with the OEM passenger handles with bungee hook studs added I decided it would be an advantage to at least add the luggage rack. Most of the time I have no need for a top case. They do come in handy if added but I have been able to get along just fine without paying to add one in the past so will see how it works out without the case for now. If I find I do want to add the top case later on I can always add it.
The Kymco branded luggage rack looks the best but I have no intention on spending over $500 on one and the more economically priced one from Taiwan Big Scooter Shop, at only $219 with rear cover, is out of stock and not available for an unknown time. That one looks best alone without a top case added and would require that I buy a mounting base or plate if I should add a top case later. The Shad top case adapters don't look like they belong on the AK to me but more like obvious after-thought tack on brackets only intended for if a top case, and side cases, are mounted. That leaves the Givi SR6110 rear rack and a mounting plate. There are a few others out there that are like the generic aftermarket tube type racks that are available for many other brands of bikes but a few are made specifically for the AK 550 as well. I prefer the look of the SR6110 over any of the others besides the Kymco brand option. And the Givi rack is easily found from many sources for a reasonable price and I would then also already have the mounting plate should I decide to add the top case later.
I did find one on eBay for way under the price of most other places but the shipping of $181 puts that one way over priced compared with several other sources. So I used Google Shopping to find the best item price plus shipping to my door from MotardInn.com. I also really like the looks and durability of the all aluminum Monokey plate from Givi, the black M8B. When I ordered these items as a set in one order I found that shipping was actually lower so my total cost for both items together shipped to my door came to $246.
It seems most pictures of the SR6110 show that rack with a silver M8 Monokey plate installed. And as a result many sources for this item say the color is silver, but that's only because the person writing the listing for it sees that silver plate and ignores the fact that the silver plate is not included, normally. This is true on the MotardInn web page and yet the listing states that the Monokey plate shown does not come with the item.
I will continue this thread with more detail and photos after I receive the rack and plate and install it on my AK 550.
Anyway, this is what I ordered and is a close indication of the actual colors. I think the black would complement the Matte Deep Blue and black of my AK rather well.