I'm surprised that Triumph haven't released something too, Dennis.....
By the time I paid for the HD copy topbox from Scootworks and accessories like liner and backrest, added the shipping charges to Aus, made the mods to the rack/sissybar (and bought another rack/sissybar for when the Chosen One is on the back without the trunk), had about 800 attempts at spraying using about 20 rattle cans(geez I'm good at wet sanding and orange peel issues now), it would have been far cheaper for me to buy the Corbin pre painted in Black/Cream (especially with the current exchange rate.)
Plus, the Scootworks Supertrunk I bought didn't have great quality control. When I undid the dozen or do small bolts holding the lid on(hinges/locks etc), I realised that they had used longer bolts than required during manufacture, and had then snipped off the extra length, leaving a very sharp, ragged edge. After spending 15 minutes working the end of one bolt simply to get the nut back on during reassembly, I gave up and went out and bought some replacements in the right length. Not really what I expect from a company that is charging a premium price for what they themselves claim is a "premium product, much better than HD". Also, the liner provided was just several strips of felt that you had to cut and join. This was a real pain with the trunk angles.....The HD liner is preformed and just drops in.
The only problem with choosing one of the 2 Corbin models is that it only has (or did, the last time I looked) a fixed trunk mount, and I wanted a quick release option.
I'm sure you've seen the Corbin (there are 2 models), but just in case.....
Corbin Motorcycle Seats & Accessories | Fleetliner & Streamliner Trunkbox | 800-538-7035
I'm sure that if Triumph made a quick release topbox at a fair price, they would definitely have a market. They already have the quick release technology in place, so you'd think development costs would be minimal.
Pete