It's difficult to find tall pitchers who are athletic enough—and have sufficient body control—to repeat their deliveries and throw quality strikes consistently. Randy Johnson is the patron saint of these pitchers (and low-slot lefthanders, a whole other phylum), and he didn't blossom until age 26. Teams may have to be patient with these giants. Top 100 Prospect ranking in parentheses.
Major league examples: Adam Wainwright, Doug Fister, Dellin Betances.
Tyler Glasnow (23) rhp, Pirates
He's nearly impossible to square up (.172 career opponent average) due to the angle the 6-foot-8 righty gets on his stuff—but walk rate of 4.4 per nine innings may not cut it.
Lucas Giolito (25) rhp, White Sox
When his delivery is in sync, he has two plus pitches with his fastball and curve. At 6-foot-6, 255 pounds, he doesn't always have everything in sync.
A.J. Puk (83) lhp, Athletics
The 6-foot-7, 220-pound southpaw needs to get stronger to maintain his delivery and its resulting power stuff, because he's not particularly athletic.