Rusty,
    Jet, Grizzly, Enco, and many others import a pretty good variety of
lathes which would do the job. These usually run from $2K-$5K, depending on
how much power you want and some other features, like gap beds. You can
check their websites for details and prices.
    The same money will buy you a nice, well cared for, used American
machine that will be FAR superior in terms of construction and a lot easier
to get parts and accessories for. I strongly suggest this route. A new
US-made Hardinge toolroom lathe with all the accessories, and bells and
whistles, would cost more than your RX-7 did new... that's pretty much out
of the question.
    I have both import machines and US made machines at my disposal, so I
know from whence I speak. We have a brand new Grizzly Bridgeport mill copy
and a pair of old Van Norman American made mills at the museum, so I am able
to make a direct comparision. The old used American machines are FAR better
than the brand new imports. Unless the machine is totally worn out, it will
be a lot better.
    I also have that little Jet 9x20 lathe at home. After having trouble
getting the three jaw chuck to repeat with any degree of accuracy, I took it
apart to see what was wrong. Nearly every screw in it was loose. I then went
over the entire lathe and found the same thing. I recently decided to tweak
the Grizzly mill at the museum and found it the same way, plus a lot of sand
left over from casting that was working its way into the moving parts. Same
thing with that 3in1 I had. The import tools just don't measure up. Q/C in a
slave labor camp just ain't that good. Parts are hard to get and may take
months to arrive, if you can get them at all.
    Best place to start looking is Ebay, and other online machine tool
sellers (there are dozens). Go to this link and start reading so what you
see will begin to make sense to you.
 http://155.217.58.58/cgi-bin/atdl.dll/tc/9-524/toc.htm
This is an Army tech manual for machine tools. It's about the best I have
found.  Email me if you need to ask questions or want help finding a good
machine. I have contacts for several machines right now. Mike C.