I'm sure you've seen pics of my CrazyBike2 and DayGlo Avenger, which have metal boxes bolted to the side(s), easily made lockable when I install the hinged lid.
I've carried everything from the batteries for the bike to dogs to dog food to groceries to other whole bikes (well, disassembled) in those pods.

I think about 160lbs is the most dog food I've had on CB2 at once, but I think I have had total about 200lbs of stuff on there, maybe a bit more, not including my own 150-160lbs (and the bike weighs about that, too). Rides horrible with that kind of load, but it does still work.

Well, as long as I don't hit any potholes, or it will break teh rear wheel (at least a few spokes, maybe trash the rim).
Then there is the Kennel Trailer, and the old-desk/bike chariot-style trailer, each of which could haul quite a lot--more than 200lbs has been hauled in each one, for miles.
The Velcro Eclipse only has a rear rack, to which I would just tie a backpack.
DGA also has a rear rack, in addition to the side pod. There's lots of options for stacking stuff on there; tied-down boxes, carry bags, backpacks, etc.
I used to use side-baskets front and rear on DGA, until I got those boxes, which work MUCH better.
I don't know what the cargo capacity will be on the new bike in progress; hopefully even higher than CB2.
I also have a 2-kid trailer but haven't used it to haul anything yet, as it is going to have a pusher assist installed, as well as brakes, so it's still in pieces. Should be able to do 150-200lbs easy, maybe more.