One of the problems with "sport-tourers" is the definition itself.
Everything from a sportsbike with soft luggage up to luxo-barges are being called "sport-tourers".
Not only is the niche small, but it's vague.
IMHO, once you get very far past a sportsbike with bags, you're simply discussing touring bikes.
For me that's about 600 lbs. When you pass that mark, you're just talking about a touring bike that may handle pretty good for a luxo-barge.
Rocker59 (aka guzzimike), Aux Arcs
Moto Guzzi Sport 1100
"Do what you can, with what you have, where you are." - Theodore Roosevelt