since you am tall and a beginner and want speed that is dangerous because you might not be comfortable on a sports bike but you might be on a dual-sport bike like handa varadero xl1000 but you've got to realize that its not the bike that goes fast its how fast the rider makes it. well what ever you do safe riding
A 'need' for speed and you want 'easier' on gas too! WOW, now that's cool, but so is Wisconsin in the winter.
Suggest you take a MSF (motorcycle safety course) before you go blasting into anywhere. You're a perfect poster boy for donor of the month at the local organ bank!
i would not strat on anything bigger than a 500 and i think it would be big enough for you too. i have a ninja 500 for my first fike and it is very fast not not so fast that you can accidentally do a wheelie or powerslide on a corner. but you can still go 60 in 2nd great and 0-6 in like 5 sec
First, don't worry about your height. I'm 6'5" and I don't have any problems on a Ninja 500R.
Second, getting a genuine sportbike wouldn't be smart as a first bike. Also, you will have to learn to control your need for speed, otherwise you'll be a number in an accident statistic soon.
I would take an MSF course and then start looking into bikes. I think the Ninja 650R would be an excellent choice - it's a sporty bike but not a genuine sportbike, it's very powerful (similar to a 350hp car) yet manageable for a beginner. You can gain experience on that bike for two or three years and then decide whether or not you want even more power.