Well....here goes my two and a half cents.
As everyone else has mentioned, you're doing the right thing by asking yourself these hard questions, and soliciting responses to them from others. That's great.
I don't think that you're in a great position to actually own a dog. And, I don't really think fostering is a good idea for you right now either...I mean, a dog still has doggie needs even if its just a foster dog. A foster dog still needs human companionship and potty and exercise time. (Sorry, Jeanne!) I think that volunteering at your local humane society would be a great option, though. I do it, and its super-rewarding. You get to hang out with lots of dogs, walk them, help people make good adoption decisions, etc. Its fantastic. And, you get to sniff puppy heads and breath without having to potty-train! WOOOOOOH! That's the best part.
I don't want to sound negative...I'm truly not. Just realistic. 11 hours a day is too much. It might be really awesome for you when you get home and get that doggie love and kisses, but what about the poor dog for all that time?
I think that Rebekah is right. You can start to make some changes that will make your life more dog friendly. It is hard to do, but its worth it. Let me give you an example. I've got a Newfie mix...Cabeza. He's 6, and really mellow, house-broken, all that. I really want a Newf pup. But, I'm in school right now and we live on the third floor of our building. Not a great time or place for a newf. So, I have to graduate, and we have to buy a house that doesn't have stairs, so that Petunia won't damage her hips. (Petunia is what I'm going to name her!) Its SO hard to wait, but I know that those things have to be in place first. Its only fair to her and to myself and to my boyfriend! hehehee!
Anyway, I hope that you explore the volunteering option, continue going to play with dogs at your dog park, and maybe dog sit for people when you have time.