Just chiming in, as a 5'2" owner of a 47cm Saluki... (52cm effective top tube on that, with a 72-degree seat-tube angle.) Set up as a traditional road bike (although with a very short-reach stem, given that I have quite short arms).
Also to say that my first Riv purchase was a 48cm first-gen (possibly second-gen?) Hillborne. Maybe I bought it from Riv in 2009 or so? It was shortly after the start of the financial crisis... Anyway, I figured that, well, of course a 48cm frame would fit... And thus started my journey into better understanding bicycle geometry. That Hillborne has an effective top tube of 54cm. Even set up as a flat-bar bike, it was wayyyy to long for me. It now belongs to my 5'8" boyfriend; it's set up as a touring bike with road bars and he uses it for touring and gravel. He loves that bike, and it fits him like a dream...
Long story short, if you are 5'2" or so and want to set up a Rivendell *with road handlebars*, you'll need an early-generation Saluki/Hilson or early-gen Atlantis.
(All that said, I once had a very-very small 1981 Nishiki Olympic 12. Tiny. With 27" wheels. That was a beautiful fit! I still regret selling that! So, somewhere out there, there are v. small UJBs that will absolutely work for quite short riders!)
I wish you all the luck in the world!
Liz S.
Washington, DC