What's up Giant Douche? Sorry, just wanted to say that. I don't know of any other -1 books, but I have only used Pinnacle, WSEX, and Canbet for baseball.
You need to have an account there and be logged in. Then go to where the run line is offered, and click on the drop down menu. They will offer from -1 to -2.5 on the favorite.
Make your own at any book or combination of books by betting ML and RL, it's been covered here several times, search baseball forum. You'll do better than taking the -1 line.