I mentioned in a previous thread, that I'd seen a van with rear leaf springs that included "anti-tramp" bars as part of the rear springs. I've been eagle eyed for the last few weeks, and I saw what I was looking for, it was a early eighties, Toyota Liteace "1.8L". I've not looked under one to confirm it's suitability in a 1200 rear springs upgrade or add-on. Have a look under one if you get a chance.

Cheers,
Chris