Here's what I ended up getting, if anyone out there even gives a unicorn's mullet... From a gentleman in a fancy home, I bought two cro-moly Miyata-built Univegas. A nice Tange Champion double-butted "Sportour" and a slightly more dinged-up (surface nicks) "Supra Sport." Quite the step up for me from the hi-ten bikes I mentioned earlier! I'm happy. Got em together for $220, which I know is a lot in some parts of the country, but a decent deal here in the Bay Area. They both ride great and fit really comfortably, which is nice because I'm 6'6". The Supra Sport is the first singlespeed project. I might keep the Sportour as-is.
Thanks for your input.