Shouldn't be that hard to find a bike that works for you. I'm about your size and while I agree that 52/53 is not an easy size to find, you can probably ride a 49cm or a 54 while continuing to look for your ideal. And sizes vary between brands as well, one that is 54cm to the top of the top tube (as Miyata measured for instance) may be 52/53 to the center. My personal stable contains a Motobecane Grand Record, a Pro Miyata, and a Centurion Turbo, which are respectively 53, 54, and 55 cm to the top of the top tube--but I am pretty sure all were sold as being 54cm. I can ride them all fine, though the GR is my favorite.

For pictures in ads where the size is not listed (or is not reliable--which is usually the case) I use as a rough gauge the distance between the top tube and downtube where they meet the head tube. If there's little to no gap between them, it's likely a 49cm. A finger-width or two gap is 52, three to four fingers 54, etc. This allows me at a quick glance to know if the frame is in the ballpark for consideration.