If you're having problems finding small enough bikes, it may be worth looking at Canyon. I know they're not easily available in the US yet but they should be later this year. The point is they are now doing the Canyon Ultimate CF in some "womens" size bikes with 650 size wheels. Just as appropriate for men I'm sure. The standard size range are beautiful bikes in person and I'm sure these are no exception. I have a 2014 Ultimate CF SL and my brother just got a 2017 Ultimate CF SLX. I'd recommend them to anyone if they fit!
They're available in a range of builds and colour schemes:

https://www.canyon.com/en-ie/road/ultimate/ultimate-cf-slx-8-0-di2-w.html


Comes with disk brakes and down to a 3XS size with a stack of 484.5mm and a reach of 350mm. I don't know how that compares with what you're already able to find but it seems pretty small to me!

Their website also has a size calculator. Dan (Slowman) will likely be more accurate but they generally seem to get it close.
You just need the info you already provided plus torso length, shoulder width and arm length (Measure method is explained in the calculator).
https://www.canyon.com/...X%20Disc%208.0%20Di2