Looks good. Definitely think about a gusset below the outrigger to spread load across the frame rail (don't want to have created a giant can opener).
Take a look at the eventual gusset on the front outriggers in this thread...
Here's a truck I've always liked. Not associated in any way and I swiped the photo off pirate. From what I was told it is similar to what you were contemplating--88" frame stretched to 100". Had a bunch of other mods too.