The old Norman portable units aren't so expensive, but if you have to upgrade to a new SuperBattery and charger that works with it, it can be, though it is a better battery than the old ones. There are people who re-cell the old batteries as well. A 200C is newer, lighter and smaller than a 200B with the same output. The 400B is the same size as a 200B with double the output, and I think it's heavier.

That's a 200B pack on my shoulder and a large tele-reflector on the flash head. The normal reflector is 5-inches in diameter. I've since replaced the 200B with a 200C. That paper on the reflector is a table I made for converting distance (readable from the focus scale on the lens) to aperture at three different power settings (200/100/50 W-s)--