I have been looking into bag stands and have been running into similar issues. I think breaking it down after a workout would be better than a stand up unit and I am only 6' tall. You have a few inches on me, it would be like boxing a little kid. I am not sure how much room you have to play with but I know Everlast makes a corner stand that would still give you enough room to park, you would just have to drag it out to use the speed bag side. They sell them @ Dick's Sporting Goods or online @ www.titlemma.com
I have played with some of the stand up bags at the gym and can easily kick and punch over them and they don't always stand so well. I prefer my 100lb bag, I even use it for grappling applications.