I'm not sure if the eB roof is strong enough for this, but a 4-door Explorer rack works great on a FSB.
You'd have to use different mounting hardware since your roof is single-wall steel, but it's a nice rack; easy to adjust, and sturdier than its rating. I've had nearly 300 lbs on mine. And they're cheap & plentiful in the JYs!
How much weight do you need to carry up there?