Dirkhead, I've read your posts on this thread twice and I don't see much definition of the riding you want to accomplish - distance, speed, frequency, load carried - beyond "roughish roads". This makes a useful recommendation problematic. Is it telling that you're interested in the fully suspended Jetstream?

Roughish roads...hmm. In addition to the Jetstream, I might suggest looking at a much less expensive and more common Dahon Mu P8 retrofitted with Schwalbe Big Apple tires, or, if you have room for it, even a Tern Eclipse P9.

Anyway, if the Jiffo appeals and, as you said, you're not adverse to buy used on ebay, there's always the classic stainless steel DaHon (or Hon): tiny folded, that stainless frame, three speed gearing, rear rack and even in collectable status much cheaper than a new Jifo.