"Touring bike" is a pretty open ended phrase. Every bike is basicly a "touring bike" if you use it to "just ride and look at the scenery".
Most factory bikes that have a "touring" version on an exsisting model (the Suzuki C90 comes to mind) just add a windscreen and perhaps some saddlebags.
The concept of just having some kind of luggage attached to the bike usualy does the trick, my FJR is more or less a sport bike, but they added hard side cases and call it a "Sport Touring" bike. (Actualy Yamaha calls it Super Sport Touring)
But then on the other hand I used to strap on a few bags to my TS 185 Suzuki and go prettty much everywhere on it. They call street/offroad capable bikes with luggage "Adventure bikes" now. (Go rent "Long Way Around")
I think most owners make the Vulcan into a "touring bike" one way or another , I added rider and passenger floorboards, extra lights, a large windscreen and highway pegs, to name a few, and would refer to the bike as a "touring" mount.
As I mentioned in the other thread, the bike is a good solo touring bike, but not a good one for two up riding.
I don't think there is any "official" description of what exactly makes a bike a "touring bike" but most would agree the bike should be comfortable, have some type of wind protection, and at least be able to carry some kind of luggage. So.........You can toss a set of nylon saddlebags on a Busa and call it a touring bike............