A friend gave me a pair of saddlebags for my XB-600. TourMaster, soft shell types. Because of the wide body plastics it fits just like a regular motorcycle. It has two support straps that go over the top and one of the straps goes across the seat bucket. But it's not a problem. In fact, with the saddlebag storage I can use the seat bucket for an additional battery. If I like the saddlebags I might upgrade to a hard shell type.
I did some searching on this forum and the internet and only came up with a few people who have tried this (a guy had them on his XB-700i. I wonder why? Wouldn't saddlebags be a good alternative to the bubble trunk that people always complain about? Plus, my motorcycle friend said bags are better for balance because a truck puts weight in the rear where it doesn't help as much. However, with bags I am concerned about security. Often saddlebags are just buckled with straps, velcro and zippers. I may have to look into how to lock / prevent easy access. I know nothing is fool-proof, but at least some prevention is better than simply pulling a zipper.
Anyway, I'll post pics as I modify and set it up, and test it out. It's raining cats and dogs right now, so I haven't actually put the bike with bags on the road. That will be the real test.
I've had saddlebags on two-wheelers for forty years. My XB600, however, has never sported them. Instead, I replaced the bubble trunk with a basket. Weight transfer is horrible, but it is capacious and compact:
You give a good overview of their plusses and minuses. One further minus is bulk. Especially with the puffy "cheeks," the X-Treme scoots would be quite "puffy" after hard cases were added.
Recently, After 20 years of riding with them, I took the hard saddlebags off my Suzuki 250
and replaced them with, ironically, a bubble trunk from another scoot. It is now a more compact package and easier to fit into my parking area. The bubble can't hold enough weight to affect balance in any case, but it's enough for tools and road gear.
If you find smallish hard cases, you might be able to cut the hip blisters off and blend the cases into the bodywork. That would save ~6" of width overall. Just don't forget that your construction needs a safety factor of at least four to account for shock loading over bumps.
Mark
Nice pics. Nice bikes. Well, my saddlebags are not hard shells, and just like you said they got the puffy look, so I'm not using them. A friend gave them to me so it's not like I paid for them. I might use them as needed -- for times when I have to take a LOT of stuff with me.