Came across this a few months ago, and added it to my very long to do list.
Finally got around to it. They're a little too big right now, but I think they'll be great in a few months.
Back -- Monkey Butt!
Suspenders, with the buttons on the straps so they can be easily adjusted.
Buttons on the pants seam -- easier access for diaper changes!
I modeled this after the overalls I made a few months ago, stopping before the bib and not sewing up the inseam.