My answer is rather sarcastic to say the least. In my mind, other than nailing/gluing up paneling or 'sizing' the walls for papering, you're only left with hanging new drywall. Sorry, but that's all I can say.
Spackeling and sanding really isn't hard work; It's mainly just time consuming. You see, the beauty of spackeling is you can put on light coatings, sand, and put more light coatings, and sand, and on and on until you get the finished product to your liking. In short, your mistakes are only as 'bad' as you leave them. Consider hiring a pro as a 'side job' for a Saturday to do the job. A 10' x 10' room might cost $150 (on the side.)