Hi Everyone...I just wanted to give an update to our situation. I decided to get him a Large dog crate...I ended up getting this one here.
Amazon.com: Midwest Life Stages Double-Door... I also got this litter box in the "mini" size to put in the back of it, and some pee pee pads to put in the littler box instead of the dog litter.
Amazon.com: Second Nature Dog Litter Pan Minature... I also got a small dog bed to put in the front of the crate.
So, his new set-up is the litter box in the back, his bed in the front. Ever since we started this, he has had NO accidents in his crate....NONE!! It's been a lifesaver for us!! He's used the box a few times, but he's mostly holding it now...and if he can't hold it, he uses the box instead of peeing in his crate! I can't express how much this has helped. I only wish I would have done this sooner! Thanks for all of your advice and I hope that everyone else who is still having issues finds a solution soon! I will try to post a picture of his set-up as soon as I can.