Are you wanting world history, US history, or what? For US history, there is "History of US" by Joy Hakim. It is a 10 volume set and goes into great detail but reads like a story. Our library has it. Depending on the 6th grader, it could be a bit much. My dd is in 5th grade and while she enjoys it, we use it as just one resource. We created a basic timeline of US history and identified key parts that we felt like diving into. We use multiple resources (library, internet, video, museums, etc) to go in depth on our targeted areas. We also always try to look at the 'way of life' for each time period. We also try to read some historical fiction as well as non fiction.
I would love to say I found the perfect curriculum, but I didn't. I can say that I enjoy history a lot more with this approach.
Amy