Those are a bit smaller than a Harley tour pak, but seem to work well!
I've got this one on my 900;
It's a 1:1 clone of a Harley king tour-pak.
The main reasons I prefer it:
1- Big as they come, as far as I've found. Don't think you can even get a bigger touring trunk
2- Has TONS of available accessories; lights, antennas, liners, organizer liners, variety of luggage racks, chrome trims, alternative hinges, backrests etc. etc.
3- Despite it being a replica, it's still very sturdy and easily carries a full load of luggage and luggage on top.
4- Wife LOVES the backrest. She says it's a whole new level of rear-seat comfort.
There are lots of replica tour paks out there, Mutazu has one, Reckless has one. It's all the same just go with the best construction you can find for your budget! Also note what things you'll need to add on! That one for $400 comes painted black, with hinges, lock, keys, and backrest.
You'll need to custom mount it. The easiest way would be to mount a wompas rack on your bike and drill the appropriate holes. Mine is mounted on a custom-welded bracked made by the previous owner (I got it second hand off of another VN900 owner). You could probably even mount it to a luggage rack IF you have a luggage rack that mounts without a sissy bar (as the sissy bar will need to be removed)..
When mounting, have your passenger (if any) sit on the bike, so you can find a comfortable spot for it to be.
Just my 2 cents. But after having the Harley tour-pak, I can't go back! Lots of my riding buddies have the Mutazu and other similar trunks. Good trunks! But they are just so small in comparison, and it is such a luxury to have that much room. I also think the Harley tour-pak looks the best, especially when you put a luggage rack on it, tail-lights and accent lights on it, etc.
I can fit 2 full face helmets, wifes purse, a jacket, couple pairs of gloves, sunglasses, few odd tools, bottle of water, etc. all in that thing at the same time. It is HUGE!