Re: Hofner?
My father owned a '60s-era German guitar (of unknown origin) that we always thought was a Framus. After researching this subject for a almost a decade (off and on), I do know a bit about Hofners, especially this style of electric guitar.
In the '60s, Hofner, Hopf, Klira, Framus (and a coupe of others that I cannot think of right at the moment) were pretty much made all in the same factory. If you really start looking into it, you'll see identical parts on each of these makes. You'll see necks that are the same on different makes, pups, tremolos, etc. And there is no rhyme or reason to it (seemingly).
In general, they are very odd guitars, but that is too harsh. They do have some redeeming qualities. In general, they are built quite well. In general, their electronics are not-so-good, and now that they are 40 years old or so, chances are they'll need some sort of electrical work.
If you want something different, you're most definately on the right track.
$650 USD seems like a lot for these guitars though. They're not "collectors" yet, and may never be.
There's a guy in Berkley, California that sells a lot of oddball guitars like this. Fat Dawg is his name, I think. You can Google it and you should find him without any problem. Be wary though, he's just as "odd" as his guitars are!
Of these German guitars like this, my favorite is the Hopf Telstar.