I'll wait for the experts to chime in, as I'm still trying to learn about lifts as well.
According to what I have learned so far, DO NOT stack blocks on other blocks. Apparently that is the main, if not only no-no in lifts.
And I think (again, wait for the experts) the 08+ 4x4 came with a 1.5" block in the rear while the 07 and before came with 2.5" block. I guess this was Ford's answer to making them slightly more aerodynamic/fuel efficient. So a swap to a 2.5" block would net you the 1" you seek. Shackles should also achieve this goal as well if you prefer to go that way. IF you do go with the blocks, they say to NEVER re-use the U-bolts and to ALWAYS replace them when you put it all back together.
That's what I have learned so far. Now I wait for someone else to follow up with some more info.