Thanks for all the info guys. The short & sweet is that my wife & I put a shed in our back yard this summer. It's nice looking, painted to match the house etc... per HOA guidelines. The one thing that may prove an issue is the stupid clause about not being visible from the street. Right now it's not thanks to all of the trees we've already planted, but come late fall that will change.
I don't know if they'll say anything (the head of our HOA is an obnoxious little woman), but we have a specific spot we're going to plant an evergreen of some sort. It can't be too big, it can't be too small, it has to meet my wife's aesthetic tastes. I also want to be careful about what kind of roots this thing will put out as it's going to be not too far from where the gas line comes in to my house.
Watering it shouldn't be an issue as it will be about 20 feet downslope from my AC unit and I plan to trench a little french drain from the condensation line to the base of the tree. Heck, I may extend and bury the line so it actually comes out underground right next to the tree.
vaskidmark, GigaBruist, thanks for the suggestions. Another magnolia off that same page looks like it might fall in the right size range. I'll show some of Giga's other suggestions to her too.
http://www.fast-growing-trees.com/little-gem-magnolia.htm