According to a blog post over at more4mini.com (formerly 9bot store), Segway may be bringing the "Segway MiniPRO Plus" to the USA later this year.
https://more4mini.com/blogs/news/segway-robot-sale
According to the article, the Plus model has larger inflatable tires--but also weighs quite a bit more (presumably due to the extra batteries needed for extended range).
I do love the styling on the new machine though
Chris